It seems likely that "white Witch" (etc.) only came into wide use during the mid to late 16th century, and it is probably no coincidence that this corresponds to the time when the most intense period of Witch Hunting was really getting under way. Prior to that time (that is, prior to the mid to late 16th century) the word "Witch", without any modification (such as "good", "white", etc.) is well attested in written sources as a designation for individuals who possessed magical and/or spiritual powers. While the term "Witch" undeniably had certain negative connotations, this had to do with the religious significance attached to "Witches" and "Witchcraft," as opposed to the strictly magical associations of those words. That is, Witches were viewed as religious enemies of Christianity, in spite of the fact that it was believed that their magical powers could cure diseases, help people to acquire wealth, divine the future, locate lost or stolen objects, provide assistance in the arena of romance, etc. Even those who insisted that these same magical powers ultimately derived from Satan (a view that does not appear to have been widely held among the common people but rather was mostly limited to religious elites) could not deny that Witches possessed such seemingly beneficial powers, and that as such they were highly valued and sought after by their neighbors, and even by those who lived far away and traveled great distances to obtain their magical aid.
Sources prior to the mid 16th century not only attest to the use of the word "Witch" as a label for workers of beneficial magic, but also as a label for such explicitly religious figures as the Witch of Endor and Simon Magus. These sources go back possibly as far as the 7th century Penitentials of Theodore, although the dating and attribution of those Penitentials is uncertain. (Of course, we find in these sources as we move back in time that "Witch" is replaced first with the Middle English "Wicche" and then with the Old English "Wicca"). Obviously, to the extent that these authors are writing from a Christian perspective they have nothing good to say about Witches, or at least they have no desire to say anything good about Witches. Therefore, as hostile witnesses, their testimony as to the beneficial magic worked by Witches is all the more convincing.
But by the time of the earliest of the sources listed below, the Christian theory of diabolical Witchcraft had become so prevalent that now people felt it was necessary to now explicitly distinguish for the first time, or, alternatively, to now begin to heavily emphasize and make much more explicit a distinction that had previously been either mostly unrecognized or was at least not viewed as requiring explicit statement in most cases, between two types of Witches: the good and the bad.
1. unknown date The White Witch of Westminster
publication date unknown, but probably Jacobean or Caroline (anywhere from 1567 to 1649)
Author unknown
See the entry in the "Lost Plays Database":
http://www.lostplays.org/index.php/White_Witch_of_Westminster,_The
"Possibly this play treated of some ' wise woman ' of Westminster who concerned herself with the love affairs of a young couple, very much as in Heywood's The Wise Woman of Hogsdon."
[Quote found in the above linked to "Lost Plays Database." This quote is from “Hill’s List of Early Plays in Manuscript," by Joseph Quincy Adams, first published in 1939.]
2. 1621 Anything For A Quiet Life
Thomas Middleton (1580-1627) and John Webster(c.1580-1634)
http://www.tech.org/~cleary/aql.html
"Free leave have I, my Lord, so I think you may have: filthy Beauty, what a white witch thou art!"
3. 1630 The Winnowing of White Witchcraft
Edward Poeton (dates uncertain)
The quote below is taken from Anti-Quack Literature in Early Stuart England by Ross Dandridge:
https://qmro.qmul.ac.uk/jspui/bitstream/123456789/3112/1/DANDRIDGEAnti-Quack2012.pdf
"this land even swarmeth in every countye and corner with white witches"
4. 1665 Daimonomageia, a Small Treatise of Sickness and Diseases from Witchcraft
William Drage (c.1636-1668)
The quote below can be found at the following url: http://witching.org/brimstone/detail.php?mode=assertions&pid=1498, which is part of the witching.org website, which int turn is part of the The Witches in Early Modern England Project created by Kirsten C. Uszkalo with funding from Social Sciences and Research Council of Canada. For a little more information on William Drage, look here: http://en.wikisource.org/wiki/Drage,_William_(DNB00)
"A sober Antient Gentleman told me, he intimately knew one in the Isle of Ely, whose name he told, but now I have forgot it; he was bewitched, and before strange fits he had like a Mouse came to him, which none could hinder; he sent to a white Witch, or Necromancer, Sorcerer, Magician, or what you please to call him; he gave him an Amulet or Charm to hang about his neck, and so long as he wore that, he was freed; he durst not leave it off: this Wizard asked if they were wicked People, else, he said, he could not, or would not help them."
5. 1681 Saducismus Triumphatus OR, Full and Plain EVIDENCE Concerning WITCHES AND APPARITIONS.
Joseph Glanvill (1636–1680)
http://archive.org/details/saducismustriump00glan
"Her use of long scriptural Prayers and Rhymes, containing the main points of Christianity, so that she may seem to have been not so much a white Witch as an holy Woman."
6. 1682 The Medal
A poem by John Dryden (1631-1700)
http://www.readbookonline.net/readOnLine/27415/
"Even in the most sincere advice he gave,
He had a grudging still to be a knave.
The frauds he learn'd in his fanatic years
Made him uneasy in his lawful gears;
At best, as little honest as he could,
And, like white witches*, mischievously good.
To his first bias longingly he leans;
And rather would be great by wicked means."
* Here is an explanatory footnote found in "The Poetical Works of John Dryden", published in 1855: "'White witches:' who wrought good ends by infernal means."
7. 1684 Pandaemonium, or, The Devil's Cloyster
Richard Bovet (born c.1641)
Source: the text given here is as quoted by Montague Summers in Witchcraft and Black Magic:
"Those particularly intended here are those such as are commonly called Black Witches, there is beside another sort termed White Witches; These by a Diabolical Complaisance, or good-nature, are to uncharm and give ease to those the other have afflicted ..."
8. 1693 Wonders of the Invisible World
Cotton Mather (1663-1728)
http://www.gutenberg.org/files/28513/28513-h/28513-h.htm
"And some learned Men are of Opinion, that the first Explorator (being a white Witch) did explicitely covenant with the Devil, that he should discover latent Crimes in this way: And that it is by Virtue of that first Contract that the Devil goeth to work to keep his Servants from sinking, when this Ceremony of his ordaining is used."
9. 1694 The trial of Henry Baron
The passage below is found in Malcolm Gaskill's Crime and Mentalities in Early Modern England (2000)
"Also in 1694, a dispute came to a head between the Crook and Baron families who shared a house at Overhilton (Lancashire). Henry Baron regularly quarelled with James Crook's wife (she had already received a warrant for his good behaviour), and when one of the Baron's calves died suddenly he accused her of witchcraft. On learning that she refused to appear before a JP, Baron was heard to say 'it was ill liveing near a white witch & ... if one did kill a white witch one could not be hang'd for it'. Soon afterwards, he beat her severely and she died. [Words in quotes are from court records dated 16 March, 1694. See Gaskill 2000 for more on the original source.]
10. 1697 A Modest Enquiry Into the Nature of Witchcraft
John Hale (1636-1700)
http://books.google.com/books?id=PdyiLmt_lzEC
(see also: http://www.archive.org/stream/historicalcollec02danv/historicalcollec02danv_djvu.txt)
"If a Magician or a white Witch (as they are called) come in to discover and testify against another to be a Witch; This (as Perkins saith, Chap. 7. p. 209) is no more then the Devil's testimony, because by the Devil's help he revealeth the Witch."
"Another sort are such as they call white witches; that by spells, charms, & c. will cure diseases, and that more easily than men can, and fetch fish bones out of men's hands, & c. Note here that the Devil hath more skill in the knowledge of all healing medicines than any man ; and more ability and dexterity to convey them insensi- bly into any sore than any mortal creature. That some have such an ambition to excel in Physick & curing variety of wounds and diseases, that they will rather go to the Devil, then fail of their desired skill and honour thereby. Many creditable Histories I have heard of this kind; but I spare to enlarge in these things which have been so fully handled by [William] Perkins."
11. 1712 THE CASE OF THE Hertfordshire WITCHCRAFT CONSIDER'D.
http://ebooks.library.cornell.edu/cgi/t/text/text-idx?c=witch;cc=witch;rgn=main;view=text;idno=wit032
"There was a certain Cunning Fellow apply'd to in this Case, under the Name of a White Witch; who, by his Prescriptions, has given us pretty broad Hints, what he took this Wench's Case to be."
12. 1717 "An Extract of the information of 25 persons at Leister assizes against an old women her son and daughter for witchcraft ...."
G. Beaumont
Source: "Witch Hunting and Witch Trails" By C. L'Estrange Ewen, Appendix VII, Depositions (18th Century): http://books.google.com/books/about/Witch_Hunting_and_Witch_Trials.html?id=jMTFNsoLyukC
"The informants all depos'd that all the supposed witches has severally their thumbs and great toes ty'd togather and that they were thrown so bound into the water, and that they swam like a cork, a piece of paper, or an empty barrell, tho they strove all they could to sinck.
"Divers of these informants depos'd that during strange illness of severall person who were bewitched as they were well assured by those persons or some of them they had the Minister to pray by them without any good effect at all, but applying to a cunning man or white witch they were directed to pt the afflicted patry's water into a bottle and set it near the fire which accordingly they frequently did and cord'd it well and ty'd down the work with 20 rounds of packthread ....."
13. 1821 Kenilworth
Walter Scott (1771-1832)
http://www.gutenberg.org/ebooks/1606
"for he was what the vulgar call a white witch, a cunning man, and such like."
14. 1829 Letters on Demonlogy and Witchcraft
Walter Scott (1771-1832)
http://www.gutenberg.org/ebooks/14461
"The principal person implicated in these heretical and treasonable undertakings was one Agnes Simpson, or Samson, called the Wise Wife of Keith, and described by Archbishop Spottiswood, not as one of the base or ignorant class of ordinary witches, but a grave matron, composed and deliberate in her answers, which were all to some purpose. This grave dame, from the terms of her indictment, seems to have been a kind of white witch, affecting to cure diseases by words and charms, a dangerous profession considering the times in which she lived."
15. 1845 Remains Historical and Literary Connected With The Palatine Counties of Lancaster and Chester, vol. VI
James Crossley (1800-1883) (from his Introduction to "Potts's Discover of Witches", which was originally published in 1613).
http://books.google.com/books?id=HP0rAAAAMAAJ&printsec=frontcover#v=onepage&q&f=false
"He who visits Pendle will yet find that charms are generally resorted to amongst the lower classes; that there are hares which, in their persuasion, never can be caught, and which survive only to baffle and confound the huntsman; that each small hamlet has its peculiar and gifted personage, whom it is dangerous to offend; that the wise man and wise woman (the white witches of our ancestors) still continue their investigations of truth, undisturbed by the rural police or the progress of the schoolmaster; that each locality has its haunted house; that apparitions still walk their ghostly rounds--and little would his reputation for piety avail that clergyman in the eyes of his parishioners who should refuse to lay those 'extravagant and erring spirits,' when requested, by those due liturgic ceremonies which the orthodoxy of tradition requires."
16. 1851 Narratives of Socery and Magic, From the Most Authentic Sources
Thomas Wright (1810-1877)
http://www.archive.org/stream/narrativessorce02wriggoog/narrativessorce02wriggoog_djvu.txt
"In course of time Butterfield left his dairy, and took a public-house in the same Tillage, where, about the beginning of the year 1751, he was troubled with fits, and, although he had been subject to similar fits in former times, these also were now ascribed to mother Osborne. He was persuaded that the doctors could do him no good, and was advised to send for an old woman out of Northamptonshire, a white witch, who had the reputation of being skilful in counteracting the effects of sorcery. This woman confirmed the opinion already afloat of the cause of Butterfield's disorder, and she directed that six men should watch his house day and night, with staves, pitchforks, and other weapons, at the same time hanging something about their necks, which she said was a charm to secure them from being bewitched themselves."
17. 1855 Westward Ho
Charles Kingsley (1819-1875)
http://www.gutenberg.org/ebooks/1860
"He devoutly believed in fairies, whom he called pixies; and held that they changed babies, and made the mushroom rings on the downs to dance in. When he had warts or burns, he went to the white witch at Northam to charm them away; he thought that the sun moved round the earth, and that the moon had some kindred with a Cheshire cheese."
18. 1861 Witch Stories
Eliza Lynn Linton (1822-1898)
http://www.gutenberg.org/ebooks/32176
"A doctor was sent for, but also, as well as the doctore, came a clever shrewed woman called Margaret Russell, or 'Countess,' a bit of a doctress in her way, perhaps a bit of a white witch too, who thought she could do the afflicted child some good...."
"But he reckoned without his host, for in 1751 he himself was bewitched; he had fits--bad fits--and sent for a white witch all the way from Northamptonshire to tell him what ailed him. The white witch told him he was bewitched; and bade six men, with staves and pitchforks hanging round their necks as counter-charms for their own saftey, watch his house night and day."
19. 1871 Legends and Traditions of Cornwall
Dublin University Magazine, Vo, 77, May, 1871
http://books.google.com/books?id=hB-ZGZw_F5AC
"His mind was agitated by the loss of his hard-earned money and his disappointed expectations, till at last he was tempted to apply to Tammy, the 'White Witch of Heselton,' who informed him in confidence that, "for a consideration," she would undertake to raise the spirit of An Jenny Hendy from her grave in Stythian's churchyard and oblige it to reveal the spot where the hoard lay concealed."
20. 1877 John Harper: The White Witch of North Devon
See this separate post on the subject: The White Witch of North Devon.
21. 1881 A Supplementary English Glossary
Thomas Lewis Owen Davies
http://books.google.com/books?id=UHMLAAAAMAAJ
"WHITE-WITCH, a wizard, or witch, not of the malicious kind."
22. 1884 The White Witch: A Novel in Three Parts
Florence Warden (1857-1929)
http://books.google.com/books?id=3aEuAAAAYAAJ
"They turned. Mr. Wayne stood on the balcony, his arms outstretched to Mary; Godfrey led her up. Lady Davenant and Mrs. Penteith were smiling on them from within the room.
"My dear little girl!--my sweet White Witch!" cried the old gentleman, with a beaming face, as he drew her to him. "Soon to be very very own little girl for ever!"
"Your very own dutiful, loving child for ever," breathed Mary; "your own little White Witch."
23. 1889 Witch, Warlock and Magician
William Henry Davenport Williams (1828-1891)
http://www.gutenberg.org/files/38763/38763-h/38763-h.htm
"Later, when Butterfield, who had given up his farm and taken to an ale-house, suffered much from fits, Mother Osborne was again declared to be the cause (1751), and he was advised to send to Northamptonshire for an old woman, a white witch, to baffle her spells. The white witch came, confirmed, of course, the popular prejudice, and advised that six men, armed with staves and pitchforks, should watch Butterfield’s house by day and night."
24. 1892 A history of the parishes of St. Ives, Lelant, Towednack and Zennor
John Hobson Matthews (1858-1914)
http://archive.org/details/ahistoryparishe01mattgoog
"No country, however enlightened, is free from superstition of the kind represented by the belief in witchcraft. Sorcery, indeed, seems to have had its votaries in every age. Mr Hunt quotes from Cornish newspapers of a very recent date, showing how one James Thomas, of Illogan, a notorious 'pellar,' or 'white witch,' duped a great number of supposed bewitched persons at Saint Ives, Hayle and elsewhere."
25. 1895 Dictionary of National Biography
Quote from the entry for Ruth Osborne
https://archive.org/details/DictionaryOfNationalBiographyVolume42_630
The wiseacres who met there attributed his misfortunes to witchcraft, and advised Butterfield to apply to a cunning woman or white-witch for a cure. An old woman was fetched from Northamptonshire, and confirmed the suspicion already entertained against Ruth Osborne and her husband John, both harmless old people over seventy years of age.