Perhaps not the best set in the world but oh well.
Groudon @ Rockium Z
Ability: Drought
EVs: X HP / 252 Atk / 256-X Spe
Adamant Nature
- Stone Edge
- Swords Dance
- Rock Polish
- Precipice Blades
Not a Primal Groudon, but it's been doing decently in a couple of test games. Speed and HP customisable for wanting to take certain hits like Precipice from other Pdons, Eruption after opposing don takes rocks (requires spdef as well as hp) and Mence's hits. I personally like to go quite a lot faster than most people would, but it doesn't mean much as +2 speed Groudon will outpace any non-scarfer on offense anyway. The reason to invest in speed would be for the stall/bulky matchups where you're wanting to get to +2 and then breaking. The basic reason for this set is that +2 Z-Stone Edge picks up KO's that regular PDon just cant quite do with the same coverage, and also gives you a 1 time Rock Type nuke that wont miss. Benchmarks like Giratina-O, Celesteela, both after rocks, and things like Bulky Mence can be reached by +2 (+1 vs mence) ZEdge that regular Pdon cant, which can mean the difference between breaking the check to things in the back, and getting Pdon dead for 70 odd on something that was only there for the PDon.
The other appealing aspect so to speak is that regular checks to Pdon like Groundceus and Zygarde struggle quite a bit more with beating regular Double Dance Groudon because they cant hit it nearly as hard, and Groudon can afford to get an extra hit off against them at least, potentially breaking the opposing team open for breaking options like Ho-oh (which is on the team I have with this because if I'm having sun anyway...). Obviously it's not going to revolutionise the meta or anything, but it can be fun if you're up against fairly standard teams, especially with Arceus-Water becoming a lot less common, and most of the Water/Grass/Ice type attackers in the tier not being used as much as they were in previous meta stages. But Zmoves give Groudon a legitimate option if you're wanting to run it. This isn't a glue mon or anything similar, and you'd need to build around this mon as opposed to it fitting naturally into a team, but it's pretty fun and I'd recommend giving it a go.