My favorite thread for machine quilting on my BERNINA is Isacord. I do free motion quilting on my art quilts and this thread seems to work best on my machine. (Your machine may prefer a different brand.)
I love to visit my local quilt shop and browse through the vast number of thread colors they offer. The colors are so enticing and each spool has a color number on the label. You’d think I’d keep track of what colors I have, but often find I’ve purchased the same beautiful colors over and over again. Aaaarrrrgh!
Isacord also has this handy way of holding the thread end so it doesn’t spool off. Pop the plastic base of the spool open, slip the thread end into the slot at the base, and snap it closed to pinch the end into place. For those of us who are neat and tidy (ha!), this little mechanism for corralling thread ends is a big help.