Oh yeah!! I have lots of "test blocks", some to see how a new technique works. I also have a bunch of mixed blocks in the same color-way from boomerang groups (3 sets total), but not enough blocks in any of the three sets to make a whole quilt.
I have a throw pillow sized cathedral window I made just to test the technique. I love the fabric choices I made and I might (someday) finish it.
I have a bunch of sampler blocks from a free BOM that I never finished because I kept finding errors in the block directions. Someday.
I LOVE making new blocks - which is why I enjoyed the boomerangs so much, and why I'm itching to make a DJ.