if you could sell them on ebay you would not get much for them, then there is the problem of posting them to the buyer.
there are none on ebay because no one wants them. Try it, make 1 and put it on ebay. The other thing is people dont pay much for stuff on ebay, great as a buyer, not as a seller
I would suggest you to list up your collages on many selling sites, if they are worth they will surely sell. Likewise, you can advertise them on social platforms also.
I don't think they would sell.A collage is something anyone can make.
Me and my friend are thinking of making collages and we can't see anything like it on eBay.. How well would they sell?