My first favorite is Beaded Tree by Kim's Crafty Apple. The embellishment with thread and bead work really makes this ACEO special.
Though Christmas is still thankfully 2 months away - wow ONLY two months! - another favorite is Santa with Two Tree Sweater from Sojourn Quilts. The fabric used is recycled - such detail in such a small size!
And, in honor of Halloween, the last Friday Favorite is Thoughtful Skeleton by Penny Fabric Art. I really couldn't pass this one up. It's got it all: an embroidered skeleton sitting in thoughtful introspection, a silk valence, and a satin rose on the included easel - all so very creative!
You can find more great ACEOs from these artists and other Quiltsy members by typing "Quiltsy ACEO" in the Etsy search field. Great examples of big creativity on a small scale.