Some guests from the Teen Wolf series would be great. The cast are all still very popular at European cons but we unfortunately don't get many of them over here anymore. Tyler Hoechlin (also plays Superman in the CW's Supergirl), Ian Bohen, JR Bourne (was also recurring in Stargate SG-1), Daniel Sharman (was also in The Originals and Fear the Walking Dead), Colton Haynes (was also a regular in Arrow.)
I'd love to see Allan Hyde and Mariana Kleveno from True Blood at this event. They are the perfect team, so funny together!!! Even just Allan on his own would be fantastic - I'd definitely buy a gold ticket just to see him again, as will a lot of my friends.