I personally would LOVE (I'll put my reasoning in these)
- Cresselia GX (not many printings)
-Uxie GX (not many printings)
-Azelf GX (not many printings)
- Leafeon GX (not many printings, eeveeloution)
-Mesprit GX (not many printings)
-Toucannon GX (Gen 7, 1 printing but would be cool)
-Hoopa both regular and unbound GX (fans love it, was playable at one point as an EX)
-Tyrantrum GX (dinosaur, kids love dinosaurs, not many printings)
- Furfrou GX (dog, kids love dogs, not many printings)
- Gogoat GX (would be interesting to see, deserved a good card)
- Pyroar female GX (did it ever get a printing on a card?)
- Volcarona GX (interesting)
- Druddigon GX (barely printed and could be a good card if they really tried)
- Klingklang GX (I thin it would be interesting but very unlikely)
- Sawsbuck GX (not many printings)
- Cofagrigus GX (not many printings, would be interesting)
- Audino GX (would be interesting)
- Zebstrika GX (got a pack art, not an ultra rare?)
- Glaceon GX (not many printings, eeveeloution)
- Huntail GX (not many printings, would be interesting)
- Solrock GX (self-explanatory)
- Lunatone GX (Self-explanatory)