I kinda like to make a mini-scrapbook for each quilt. I just started doing that the last couple of quilts & it's super fun! I include the names/designer/manufacturer of the fabrics I used, the threads used to piece/applique/quilt, reference any notions used & talk about anything I think of that makes the quilt extra special ... like the fact that a fabric was a repro of a dress my grandmother had when she was a little girl, or why I chose to go with a particular design & what I know about the history of that design (or a couple drafts of it showing my design process if it's an original). And, of course, I put who I made it for, when & where. I add photos, sketches, scraps of material & whatnot to add visual & tactile interest. If I've inked/dyed any of the fabrics, I include what I used for that process & which colors.
The one thing I leave out is the one tiny special touch that goes into all my family quilts. I think it's fun to leave it out there as a mystery. It's fun to imagine someone generations from now will look at the quilts I did for family members and notice the one thing they all have in common.