One resource that some may not be aware of is Albert Cook Myers, Notes on Immigrants to Pennsylvania, 1681-1737, vols. 1–54, LDS microfilms 567010 through 567023. This is a massive collection of his notes, many from obscure sources, arranged alphabetically by last name, first name. Another resource is Albert Cook Myers, Notes on English Quakers in Pennsylvania, late 17th & early 18th, LDS microfilms 567024-567027. These microfilms are apparently available only at FamilySearch centers.