This is very nice of you to offer! Here's John himaru-kun.deviantart.com/art/… his ref sheet has been updated a bit since I ordered a commission of him from you a long time ago. Seeing more art your own characters is always awesome, though.
That's what an ACEO is, and original card about 2.5 x 3.5 inches in size. ACEO stands for Art Cards, Editions and Originals and was done often among artists professionally in the past or just for fun among each other. Recently people have started to do them again.
o3o Oh interesting, hmm I guess I'll leave a character here then kind of curious to see these ACEOs whether I get chosen or not really! My main, Shazy, a folder with all the refs I have of her at the moment until I can create a ref sheet in june sta.sh/21r7ie2u9wre?edit=1