The links below contain rich resources for finding free dulcimer tablature:

DulcimerTab.com • Dulcimer Tablature – free downloads
Kudzu Patch – Ben Seymour’s Tablature
Colorado Dulcimer DAD
Dogwood Dulcimer Gulfweb – all tunes, alphabetically
Terry Lewis (hymns in DAD)
3 River Dulcimer
Bellingham Dulcimer Club
Stephen SeifertLesson
N.Georgia Foothills- Tuesday Morning Tab Book
Tab Archives-Tull Glazener
Tindle Music Company Tab
Jessica Comeau – Lessons and Tab
Doofus Music Tablature Page
MMDulcimerss
DAA Dulcimer Tab
Index of /vaudeville/Tabs/Dulcimer/DAA
Turlough O’Carolan
Shelly Stevens TAB from 2011 – 2016
Shelly Stevens TAB from 2005-2010 (with some TAB for 1+ fret)
Western North Carolina Collective Free Tab
Digital Tradition Folk Music Database (sound files, not TAB)
Third Sunday Gathering (3SG) (lots of tab in DAA, some in DAD)