New Skin Idea: Gatekeeper Thresh
Honestly, Gatekeeper Galio is one of my all-time favorite skins (possibly due to Galio being one of my favorite champions). I think that Riot could do so much with the Gatekeeper skin series. WIth Thresh specifically, his ultimate could turn into a pentagram while his pull would spawn a gate animation that closes as he pulls something (or himself) through it. Obviously this skin would be one of the higher tiers. I think that the Gatekeeper series (If it were to continue) would be a perfect fit for Thresh and the "underworld-ly" air about him.