> it's sort of annoying that I can't simply hand over this list of other projects I've passed and say "here, all of these companies thought this was good". Why

> it's sort of annoying that I can't simply hand over this list of other projects I've passed and say "here, all of these companies thought this was good". Why not? Put them in a repository, and in your cover letter when applying to a new company paste a link to it, and say exactly that. It's your code after all.