Sadly there are very few brick and mortar long arm supply retailers, most are on line. Most quilt shops are only carrying threads for domestic use so rarely do they stock the big cones in any quantity or variety. Your best bet is to see if there is a LA dealer in the area. They would be the most likely to have a good assortment of threads.
I order almost all my thread on line or save up and purchase a lot at the big national shows and that seems to be the way most of us shop for thread. The major vendors are at the big shows (AQS Quiltweeks, Road to California, etc) and almost always have a deal going. I agree with quiltingshortimer you should get thread cards for the brands you like so you can order on line. I use a lot of different threads but my favorite is Glide thread by Filtec. It is a 40 wt trilobal polyester originally marketed to machine embroidery, very similar to Superior Magnifico. I have the color cards for Glide. Years ago they used to give them away at the shows, sadly that is no longer the case.
Edited to add, if most of your quilting is charity quilts I would just get a few neutrals. Surprisingly, I have discovered that sage green (like pea soup) and golds seems to play nicely with everything. I always have white on hand as well.
Last edited by feline fanatic; 02-26-2020 at 05:19 AM.