Jordan's in Oregon
https://jordanfabrics.com/ has precut block sets. Her fabrics are quilt shop quality and laser cut, so the cut is very precise.
There is a lady on Ebay cabe6677 who sells precut fabric kits. I have bought several but don't really like sewing block pieces that still have the selvedge on them so I haven't bought from her lately. Her cuts are pretty good. I like making HSTs with squares of fabric and hers are always triangles. I have to watch the bias with her cuts. She is reasonable.