You should actually try and put them on Craiglist and see what happens. I've been slowly getting rid of my GPUs on there and basically sold an average of 1 every month or so. However with this covid19 mess all of a sudden I quickly sold 5x as much in a single month.

Basically most people were buying them for their kids to build a gaming PC to keep them occupied. The prices haven't really gone up but at least they are selling quicker and might be a good time to sell any 4GB you got laying around.