Saw someone talking about this earlier, so...
Nominating Rhyperior to B-.
First, let's start by talking about how it's pretty much the hardest counter to Bird Spam. It can easily come in on any of Talonflame, Staraptor, and Mega Pinsir's (bar +2 Close Combat on the switch) moves with ease, while the opponent is forced to switch out most of the time, getting you a free turn to set up stealth rock. Here's a replay showing the capabilities of Rhyperior against a Bird Spam team.
http://replay.pokemonshowdown.com/ou-228047932
I know this is a rather lackluster replay do to the little time Rhyperior got to actually go in, but unfortunately it's the only one I have at the moment. Due to the presence of Rhyperior on my team, however, his Talonflame (which was Choice Band I believe) was either forced to Flare Blitz and get walled by Rhyperior or pivot out of there. In the end of the replay, Rhyperior easily stopped the 3 last pokemon on his team. I was also able to set up stealth rock due to Rhyperior checking his Choice Specs Raikou.
Speaking of Electric types, Rhyperior can also deal with the majority of them. In the replay provided, Rhyperior was able to come in on Raikou's Volt Switch with ease, forcing a switch and being able to get stealth rock up. This is also the case with several other electric types as well, such as Mega Manectric and non-Grass Knot Thundurus. Thanks to Solid Rock and Hidden Power's low base power, Rhyperior can tank Hidden Power Ice from all 3 of these pokemon pretty well (though Choice Specs Raikou is a 2HKO).
Rhyperior also has a wide movepool. Stealth Rock is an essential component on any team, and Rhyperior can often find many opportunities to set it up. Earthquake can easily OHKO a majority of the electric types in the tier and can do a decent amount of damage to non-resists. Stone Edge takes out the Flying Types that Rhyperior counters hard. The fourth moveslot is whatever the team needs the most. Ice Punch can be used to smack Garchomp or Landorus-T predicting an earthquake pretty hard. Fire Punch can be used to muscle pass Scizor and Ferrothorn lacking Power Whip. Toxic is also a viable option as well, crippling pokemon that come in to tank hits from Rhyperior. Dragon Tail and Roar can also be used to get hazard damage on forced switches.
Rhyperior seeks competition with other bulky ground types, such as Garchomp, Hippowdon, and Landorus-T. The main advantage that Rhyperior has over them is the rock typing, allowing Rhyperior to wall flying types to no end. One of the downsides of using Rhyperior is the lack of recovery besides leftovers, but this can be fixed with Wish Support. Rhyperior's weaknesses to common types, such as grass, water, ground, and fighting, can all be covered by another pokemon that Rhyperior has good synergy with, such as Mega Venusaur or Tangrowth.
To conclude, Rhyperior is a rather solid (no pun intended) pokemon in the metagame, having the niche as a Stealth Rock Setter that can check Bird Spam and VoltTurn cores. It's great ability in Solid Rock allows Rhyperior to beat many pokemon with the correct coverage, such as Mega Scizor and Garchomp.
Relevant Calcs
Nominating Rhyperior to B-.
First, let's start by talking about how it's pretty much the hardest counter to Bird Spam. It can easily come in on any of Talonflame, Staraptor, and Mega Pinsir's (bar +2 Close Combat on the switch) moves with ease, while the opponent is forced to switch out most of the time, getting you a free turn to set up stealth rock. Here's a replay showing the capabilities of Rhyperior against a Bird Spam team.
http://replay.pokemonshowdown.com/ou-228047932
I know this is a rather lackluster replay do to the little time Rhyperior got to actually go in, but unfortunately it's the only one I have at the moment. Due to the presence of Rhyperior on my team, however, his Talonflame (which was Choice Band I believe) was either forced to Flare Blitz and get walled by Rhyperior or pivot out of there. In the end of the replay, Rhyperior easily stopped the 3 last pokemon on his team. I was also able to set up stealth rock due to Rhyperior checking his Choice Specs Raikou.
Speaking of Electric types, Rhyperior can also deal with the majority of them. In the replay provided, Rhyperior was able to come in on Raikou's Volt Switch with ease, forcing a switch and being able to get stealth rock up. This is also the case with several other electric types as well, such as Mega Manectric and non-Grass Knot Thundurus. Thanks to Solid Rock and Hidden Power's low base power, Rhyperior can tank Hidden Power Ice from all 3 of these pokemon pretty well (though Choice Specs Raikou is a 2HKO).
Rhyperior also has a wide movepool. Stealth Rock is an essential component on any team, and Rhyperior can often find many opportunities to set it up. Earthquake can easily OHKO a majority of the electric types in the tier and can do a decent amount of damage to non-resists. Stone Edge takes out the Flying Types that Rhyperior counters hard. The fourth moveslot is whatever the team needs the most. Ice Punch can be used to smack Garchomp or Landorus-T predicting an earthquake pretty hard. Fire Punch can be used to muscle pass Scizor and Ferrothorn lacking Power Whip. Toxic is also a viable option as well, crippling pokemon that come in to tank hits from Rhyperior. Dragon Tail and Roar can also be used to get hazard damage on forced switches.
Rhyperior seeks competition with other bulky ground types, such as Garchomp, Hippowdon, and Landorus-T. The main advantage that Rhyperior has over them is the rock typing, allowing Rhyperior to wall flying types to no end. One of the downsides of using Rhyperior is the lack of recovery besides leftovers, but this can be fixed with Wish Support. Rhyperior's weaknesses to common types, such as grass, water, ground, and fighting, can all be covered by another pokemon that Rhyperior has good synergy with, such as Mega Venusaur or Tangrowth.
To conclude, Rhyperior is a rather solid (no pun intended) pokemon in the metagame, having the niche as a Stealth Rock Setter that can check Bird Spam and VoltTurn cores. It's great ability in Solid Rock allows Rhyperior to beat many pokemon with the correct coverage, such as Mega Scizor and Garchomp.
Relevant Calcs
252 Atk Choice Band Staraptor Close Combat vs. 212 HP / 252 Def Solid Rock Rhyperior: 183-216 (43.1 - 50.9%) -- guaranteed 3HKO after Leftovers recovery (Rhyperior OHKO's back with Stone Edge)
252+ Atk Choice Band Talonflame Brave Bird vs. 212 HP / 252 Def Rhyperior: 77-91 (18.1 - 21.4%) -- possible 7HKO after Leftovers recovery (Rhyperior OHKO's back. If Talonflame is a Stall Breaker set and burns Rhyperior on the switch, Stone Edge still OHKO's)
+2 252 Atk Mega Pinsir Close Combat vs. 212 HP / 252 Def Solid Rock Rhyperior: 294-346 (69.3 - 81.6%) -- guaranteed 2HKO after Leftovers recovery (Rhyperior OHKO's with Stone Edge)
252 SpA Mega Manectric Hidden Power Ice vs. 212 HP / 0 SpD Solid Rock Rhyperior: 163-193 (38.4 - 45.5%) -- guaranteed 3HKO after Leftovers recovery (Earthquake is a OHKO after stealth rock)
252 SpA Life Orb Thundurus Hidden Power Ice vs. 212 HP / 0 SpD Solid Rock Rhyperior: 201-238 (47.4 - 56.1%) -- 25.4% chance to 2HKO after Leftovers recovery (Assuming you switch into Thunder Wave or Thunderbolt, non-Focus Blast/Grass Knot Thundurus is OHKO'd by Stone Edge)
252 SpA Raikou Hidden Power Ice vs. 212 HP / 0 SpD Solid Rock Rhyperior: 145-172 (34.1 - 40.5%) -- 50.5% chance to 3HKO after Leftovers recovery (Earthquake is a OHKO. Choice Specs Raikou can 2HKO with HP Ice)
+2 252+ Atk Tough Claws Mega Charizard X Dragon Claw vs. 212 HP / 252 Def Rhyperior: 250-295 (58.9 - 69.5%) -- guaranteed 2HKO after Leftovers recovery (Both STABs are a OHKO)
252 Atk Landorus-T Earthquake vs. 212 HP / 252 Def Solid Rock Rhyperior: 177-208 (41.7 - 49%) -- guaranteed 3HKO after Leftovers recovery (Rhyperior 2HKO's with Ice Punch and can OHKO with stealth rock and some prior damage)
252 Atk Garchomp Earthquake vs. 212 HP / 252 Def Solid Rock Rhyperior: 163-193 (38.4 - 45.5%) -- guaranteed 3HKO after Leftovers recovery (Choice Scarf Garchomp is OHKO'd by Ice Punch after stealth rock)
0 Atk Gliscor Earthquake vs. 212 HP / 252 Def Solid Rock Rhyperior: 100-121 (23.5 - 28.5%) -- possible 5HKO after Leftovers recovery (Ice Punch has a chance to OHKO specially defensive Gliscor after stealth rock)
+2 84 Atk Technician Mega Scizor Bullet Punch vs. 212 HP / 252 Def Solid Rock Rhyperior: 193-229 (45.5 - 54%) -- 2.3% chance to 2HKO after Leftovers recovery (Fire Punch is a 2HKO, so prior damage is needed to check Bulky Sword Dance Scizor)
0 Atk Ferrothorn Gyro Ball (72 BP) vs. 212 HP / 252 Def Solid Rock Rhyperior: 73-87 (17.2 - 20.5%) -- possible 7HKO after Leftovers recovery (non-Power Whip Ferrothorn can't do much to you, while you can 2HKO with Fire Punch)
252+ Atk Choice Band Talonflame Brave Bird vs. 212 HP / 252 Def Rhyperior: 77-91 (18.1 - 21.4%) -- possible 7HKO after Leftovers recovery (Rhyperior OHKO's back. If Talonflame is a Stall Breaker set and burns Rhyperior on the switch, Stone Edge still OHKO's)
+2 252 Atk Mega Pinsir Close Combat vs. 212 HP / 252 Def Solid Rock Rhyperior: 294-346 (69.3 - 81.6%) -- guaranteed 2HKO after Leftovers recovery (Rhyperior OHKO's with Stone Edge)
252 SpA Mega Manectric Hidden Power Ice vs. 212 HP / 0 SpD Solid Rock Rhyperior: 163-193 (38.4 - 45.5%) -- guaranteed 3HKO after Leftovers recovery (Earthquake is a OHKO after stealth rock)
252 SpA Life Orb Thundurus Hidden Power Ice vs. 212 HP / 0 SpD Solid Rock Rhyperior: 201-238 (47.4 - 56.1%) -- 25.4% chance to 2HKO after Leftovers recovery (Assuming you switch into Thunder Wave or Thunderbolt, non-Focus Blast/Grass Knot Thundurus is OHKO'd by Stone Edge)
252 SpA Raikou Hidden Power Ice vs. 212 HP / 0 SpD Solid Rock Rhyperior: 145-172 (34.1 - 40.5%) -- 50.5% chance to 3HKO after Leftovers recovery (Earthquake is a OHKO. Choice Specs Raikou can 2HKO with HP Ice)
+2 252+ Atk Tough Claws Mega Charizard X Dragon Claw vs. 212 HP / 252 Def Rhyperior: 250-295 (58.9 - 69.5%) -- guaranteed 2HKO after Leftovers recovery (Both STABs are a OHKO)
252 Atk Landorus-T Earthquake vs. 212 HP / 252 Def Solid Rock Rhyperior: 177-208 (41.7 - 49%) -- guaranteed 3HKO after Leftovers recovery (Rhyperior 2HKO's with Ice Punch and can OHKO with stealth rock and some prior damage)
252 Atk Garchomp Earthquake vs. 212 HP / 252 Def Solid Rock Rhyperior: 163-193 (38.4 - 45.5%) -- guaranteed 3HKO after Leftovers recovery (Choice Scarf Garchomp is OHKO'd by Ice Punch after stealth rock)
0 Atk Gliscor Earthquake vs. 212 HP / 252 Def Solid Rock Rhyperior: 100-121 (23.5 - 28.5%) -- possible 5HKO after Leftovers recovery (Ice Punch has a chance to OHKO specially defensive Gliscor after stealth rock)
+2 84 Atk Technician Mega Scizor Bullet Punch vs. 212 HP / 252 Def Solid Rock Rhyperior: 193-229 (45.5 - 54%) -- 2.3% chance to 2HKO after Leftovers recovery (Fire Punch is a 2HKO, so prior damage is needed to check Bulky Sword Dance Scizor)
0 Atk Ferrothorn Gyro Ball (72 BP) vs. 212 HP / 252 Def Solid Rock Rhyperior: 73-87 (17.2 - 20.5%) -- possible 7HKO after Leftovers recovery (non-Power Whip Ferrothorn can't do much to you, while you can 2HKO with Fire Punch)