This was a really tiny baseball card sized art piece entitled "Gazing Star"... 2.5" x 3.5" that I sold on eBay in 2012 if I remember rightly. Drawn on two plys of cardstock using ink pen and colored pencils and then painted over with water based acrylics, I don't think I sealed this one with varnish afterward like I usually do.
I'm pretty fond of ACEO and tiny "small format" art in general and I've amassed a collection from other people but I also like to make my own. I sell some and keep others... and I have mini frames I use to display them.
Not an expert but I'm always learning. Have you ever tried painting small format art pieces? Have you ever collected ACEOs from other artists?