[Toraen]

A decent/common set is:

Palkia @Leftovers/Lum Berry
Trait:Wonder Guard
EVs: 252 HP / 252 Atk / 252 Def / 252 SAtk / 252 SDef / 252 Spd
Timid/Modest
-Spacial Rend/Dragon Pulse
-Magic Coat/Substitute
-Shell Smash
-Aura Sphere/Water Spout/Gastro Acid

I actually see a fair amount of dragons, but Wonder Guard Dialga is the only common dragon that feels safe switching in to Palkia's Spacial Rend. Palkia can carry Aura Sphere for that though. Aura Sphere is also great for any non-ghost evasion abusers (evasion isn't that common but it can really mess with teams that don't expect it). Giratina probably won't try to set up against boosted Spacial Rend though, so they're not much of an issue.

You could put Gastro Acid on this to try and play around other Wonder Guarders, but I feel that those are better dealt with by using other team members. Most teams have multiple WGers and can just switchstall Gastro when you lack any other method of hurting them. You can also probably just Magic Coat their status moves if you want to keep Palkia in anyway.

Also Relados, that Deoxys team is trolled pretty hard by Wonder Guarders with U-turn and Magic Coat. Also you lose if any hazards end up on your side and they have a Pure Power sweeper.