Staraptor @ Leftovers  
Ability: Intimidate  
EVs: 252 HP / 252 Def / 4 SpD
Impish Nature  
- Brave Bird / U-Turn
- Defog / Toxic
- Toxic / Close Combat / Taunt
- Roost

Role
If you want to use something else than Skarmory, Staraptor might be a fun pick for you! Base 70 def might seem bad but intimidate really helps it out a lot and it can also help its less bulky teammates that way. Also provides defog support and can spread Poison.

Set
Max Defense and HP makes 'raptor as bulky as possible on the defensive side. Speed EVs aren't needed because it doesnt outspeed anything noteworthy with it without giving up too many defensive EVs. The moveset is pretty standard. Combine U-Turn and Taunt to be able to switch out after you taunted Shuckle. Rocky Helmet can be used to cripple physical attackers but that's all up to you.  

Calcs (Defensive)
-1 252+ Atk Groudon-Primal Stone Edge vs. 252 HP / 252+ Def Staraptor: 184-218 (36.5 - 43.2%) -- 98.4% chance to 3HKO after Leftovers recovery
-1 252+ Atk Thick Club Marowak-Alola Flare Blitz vs. 252 HP / 252+ Def Staraptor: 244-288 (48.4 - 57.1%) -- 42.6% chance to 2HKO after Leftovers recovery (120 Attack from Arceus)
-1 252 Atk Heracross-Mega Rock Blast (5 hits) vs. 252 HP / 252+ Def Staraptor: 220-270 (43.6 - 53.5%) -- approx. 0.4% chance to 2HKO after Leftovers recovery
-1 252 Atk Tyranitar-Mega Stone Edge vs. 252 HP / 252+ Def Staraptor: 236-278 (46.8 - 55.1%) -- 67.2% chance to 2HKO after sandstorm damage and Leftovers recovery
-1 252 Atk Choice Band Crobat Brave Bird vs. 252 HP / 252+ Def Staraptor: 196-232 (38.8 - 46%) -- guaranteed 3HKO after Leftovers recovery (150 Attack from Groudon)
-1 252+ Atk Life Orb Smeargle Extreme Speed vs. 252 HP / 252+ Def Staraptor: 125-148 (24.8 - 29.3%) -- possible 5HKO after Leftovers recovery (150 Attack from Groudon)
252 SpA Contrary Serperior Leaf Storm over 2 turns vs. 252 HP / 0 SpD Staraptor: 455-536 (90.2 - 106.3%) -- 62.5% chance to 2HKO after Leftovers recovery (120 SpA from Arceus)

Calcs (Offensive, just some mons it KOs, it's not really a sweeper set so...)
0 Atk Staraptor Brave Bird vs. 252 HP / 144+ Def Buzzwole: 372-444 (88.9 - 106.2%) -- guaranteed OHKO after Stealth Rock and Leftovers recovery
0 Atk Staraptor Brave Bird vs. 0 HP / 0 Def Serperior: 318-374 (109.2 - 128.5%) -- guaranteed OHKO
0 Atk Staraptor Close Combat vs. 0 HP / 0 Def Tyranitar-Mega: 284-336 (83.2 - 98.5%) -- 68.8% chance to OHKO after Stealth Rock