I've been putting orphan blocks in a plastic bin for the past several years. Some of the blocks are one time trial blocks or color studies, some are a few extra blocks from a project, some are from downsizing a quilt and there is a least one section of strip piecing I never cut into blocks!
All together they are bright, vibrant and create interesting activity in the quilt top.
It's still very much a work in progress. There are hundreds of loose threads that need to be clipped. These blocks that have been sitting around are messy! And I'm trying to decide if I want to put a border on it to make it a better twin size quilt. I'm still not sure what I want the final quilt to look like!