I use a variety...Guterman; coats & clark; americana (found at JoAnn's for $1/spool). As long as they are labeled hand-quilting I'm not too picky. Color is more important to me. The Americana brand at JoAnns does have a tendency to be a bit heavier and I have difficulty using it with the #12 Roxanne needles. It's usually ok with the #11's. I also like to use Thread Heaven to condition the thread vs. beeswax.