He is a Funatic, a member of the Funko Funatic Boards.
His name is Tim Gilardi, but he likes to go as Timmaytimmtim on the interwebs. Feel free to look around his site.
Tim says on his tumblr page ..
"I make ‘em! I think the Pop! vinyl style is awesome so I thought others would enjoy it as well. Funko may never get the licences to make some characters so I thought it would be fun to make what I thought they would look like.
Thank you for the interest! If you have any characters you’d like to see let me know i’ll see what I can do.