For the topic at hand; there's actually a number of decks I really want to try out with the addition of Guardians Rising:
1. Lycanroc/Carbink
Lycanroc is a huge favorite new pokemon of mine from Sun/Moon, so seeing that both forms are potentially viable is super exciting to me.
2. Lurantis/Bulu
I built a Lurantis/Plume deck that kinda crashed and burned, so, seeing another viable option for Lurantis is exciting.
3. Garbodor
Easily the most absurd non-GX card I've seen in a while; I'm definitely gonna try and fiddle with this guy.
EDIT:
OH RIGHT, how could I forget Vikavolt GX?! He was a bit underwhelming to me at first, but, after thinking about it I could see it working really well with an Eels engine in expanded, and just slapping Electrode onto him in Standard. Potentially splash Tapu Koko in there so you fast swap if Vika gets heavy damage? Not to mention it just destroys Shaymins and Mega Ray if you slap a wide lens on it.