Regirock
Regirock apparently hasn't seen too much usage up until this point, but I'm thinking his ability to set up rocks and check birds, coupled with his stellar defensive stats, will cause him to rise dramatically.
Here's an old set from DPP that's still very functional:
Tank
-Stone Edge
- Earthquake
-Stealth Rock
- Toxic/Thunderwave/Drain Punch/
item: leftovers
ability: Clear Body
204 HP / 148 Atk / 156 SpD
Adamant/Careful
This set serves more of a utility purpose, setting up rocks, and checking birds, while throwing up rocks. This set has a bit of a bite with 148 atk investment, and can actually do decent amounts of damage, potentially with unresisted coverage. The EVs can be changed to max defense max HP to better hold off swellow, altaria, and the like.
Curse
-Rock Slide
-Curse
-Rest
-Sleep Talk
item: leftovers
ability: Clear Body
252 HP / 252 SpD / 4 Spe
Careful Nature
Curse is an alternative option Regirock has. Though it's typing and low attack off the bat are somewhat hindering, very little in NU can stop this set after a curse or two. It takes a super effective attacks such as hydro pump from Gorebyss to bring it down. The set is walled by Quagsire, and struggles against Things like Alomomola, but with proper team support, It can decimate apposing teams. Cacturne makes a good partner as it's able to set up spikes, and directly threaten water types that threaten regirock. Be sure to have a solid fighting resist if you plan on using the two as threats like Sawk still stand out.
It holds it's own quite well against a ton of threats thanks to 80/200/100 defenses, and edge-quake provides excellent coverage. Anyway, I'm expecting to see a lot of Regi's running around, though I feel my grasp on NU is very loose. In any case, please discuss!