I bought a $5 “moving blanket” from Harbor Freight. It’s not large, but it’s “quilted” and decently made. It lives in the back of our minivan to protect the van from muddy bikes, or if we’re moving stuff it can be stuffed between the stuff and the sides of the van, and in a pinch I guess you could use it as a blanket (yes, you have to wash it occasionally!) And it’s been a beach blanket or picnic blanket at times as well. I mean it’s basically just a tough blanket thing and it was $5.