I use any thread I want on my Brother PQ1500. I can use coats and Clark, aurafil, wonderfil, isacord, glide, and lately have been using the coats and Clark serger thread for FMQ. They all work. Depends on the look. The trilobal polyesters like Isacord give a different look. Practice with different threads and see what you like. My machine is happy with a 90/10’ top stitch needle with any of the threads.