Gen 9 Random Doubles Battle:
-Bastiodon can now run Rest.
-Probopass now has a second setup set, with Power Gem instead of Flash Cannon as its STAB move.
-Arceus-Dragon: -Aura Sphere, -Earth Power, +Tera Fire.
-Both Urshifu formes have been revamped so that they always run their priority move.
-Garganacl now runs Stealth Rock.
-Iron Moth's Acid Spray set no longer runs Fire Blast, and always runs Heat Wave.
-Iron Valiant: -Taunt, +Encore.
-Chien-Pao's sets have been split to ensure that it always runs Sucker Punch.
-Doubles Support Fezandipiti: -Taunt, +Play Rough.
-Regigigas runs Leftovers.
Old Gens:
The changes below reduces or eliminates (depending on the generation) the likelihood that teams will have multiple Stealth Rock users.
-In Gens 4-7, Registeel now runs Thunder Wave on its Staller set; hardcoded to only generate if the team already has a rocker.
-In Gens 4-7, Wormadam-Trash now runs Sucker Punch; hardcoded to only generate if the team already has a rocker.
-In Gens 5-7, Wormadam-Sandy now runs Sucker Punch; hardcoded to only generate if the team already has a rocker.
-In Gens 4-5, Shuckle has been revamped so that it always runs Toxic, Encore, Stealth Rock, and one of Knock Off and Protect; when the team already has a rocker, it doesn't run Stealth Rock and runs both Knock Off and Protect.
-In Gens 4-7, lead Focus Sash no longer generates unless the set contains a hazard or setup move.
-In Gen 4-7, Plusle and Minun now run a Life Orb setup set with Nasty Plot, Thunderbolt, HP Ice, and Grass Knot.
-In Gens 4-7, Arceus-Poison always runs a Ground coverage move: Earthquake on non-setup and Earth Power on setup.
-In Gens 5-7, Chansey's sets have been combined for simplicity. To facilitate this, the Staller role no longer enforces Wish.
-In Gens 5-7, non-setup Thundurus now runs Superpower instead of Focus Blast.
-In Gens 6-7, Meganium now runs Energy Ball instead of Giga Drain.
-In Gens 6-7, Blaziken-Mega now always runs Swords Dance.
-In Gens 6-7, Mega Metagross always runs Zen Headbutt, and no longer runs Ice Punch.
-In Gens 6-7, Deoxys and Deoxys-Attack no longer run Fire Punch.
-In Gens 6-7, Bronzong always runs Earthquake.
-In Gens 6-7, Arceus-Fire no longer runs Thunderbolt and Ice Beam, and runs Energy Ball. Its non-Z set always runs Recover.
-In Gens 6-7, Bulky Support (Synthesis) Chesnaught no longer runs Leech Seed, and runs Bulk Up and Toxic.
-In Gen 7, Aerodactyl now runs a Z-Flying set with Sky Attack, Hone Claws, Stone Edge, and Earthquake.
-In Gen 7, Raticate-Alola now runs a Z-Normal set with Double-Edge, Swords Dance, Knock Off, and Sucker Punch.
-In Gen 7, Exeggutor-Alola now runs an AV set with Knock Off.
-In Gen 7, Grumpig runs a Gluttony Recycle Calm Mind set with a 50% healing berry.
-In Gen 7, Setup Sweeper Comfey can now run Synthesis, which rolls with Giga Drain.
-In Gen 7, Nihilego always runs Power Gem.
-In Gen 6, Purugly now runs Wake-up-slap to hit Rock and Steel types.
-In Gen 6, Lucario-Mega's physical set runs Adaptability boosted Iron Tail instead of Ice Punch.
-In Gens 4-5, Espeon and Mesprit now run HP Fighting instead of HP Fire.
-In Gens 4-5, physical Lucario now runs Stone Edge instead of Ice Punch.
-In Gens 4-5, Dusknoir now runs a Staller set like in Gens 6-7, with Shadow Sneak, Toxic, Protect, and Earthquake. Toxic has also been added to its Bulky Attacker set.
-In Gen 5, Scolipede no longer runs Quick Feet.
-In Gen 5, Regice can now run Thunder Wave and Focus Blast on its Bulky Attacker set.
-In Gen 4, Sunny Day Vileplume always runs HP Fire and no longer runs Synthesis.
-In Gen 4, Bellossom can now run Leech Seed.
-In Gen 4, Steelix now runs a Staller set with Earthquake, Toxic, Protect, and Iron Head.
-In Gen 4, Mantine now runs two sets. Both sets run Surf and Toxic; the first runs RestTalk, and the second HP Flying and Protect.
-In Gen 4, Purugly no longer runs Taunt and runs Iron Tail (enabling Choice Band).
-In Gen 4, every bulky Rotom forme now runs a RestTalk set.
-In Gen 3, Slaking always runs Hyper Beam, and no longer runs Focus Punch.
-In Gen 3, Steelix no longer runs RestTalk; instead, it has a Staller set with Toxic and Protect.
-In Gen 2, Electrode can now run Thunderbolt on its set with screens.
-In Gen 2, Jumpluff no longer has its attackless set.
Technical:
-In Gens 5-7, High Jump Kick Mienshao will always have odd HP, even when its ability is Regenerator.
-In Gens 4-7, Pokemon 4x weak to Rock will have odd HP even if their item is Life Orb or Leftovers.
Gen 9 Random Doubles Battle: -Bastiodon can now run Rest. -Probopass now has a second setup set, with Power Gem instead of Flash Cannon as its STAB move. -Arceus-Dragon: -Aura Sphere, -Earth Power, +Tera Fire. -Both Urshifu formes have been revamped so that they always run their priority move. -Garganacl now runs Stealth Rock. -Iron Moth's Acid Spray set no longer runs Fire Blast, and always runs Heat Wave. -Iron Valiant: -Taunt, +Encore. -Chien-Pao's sets have been split to ensure that it always runs Sucker Punch. -Doubles Support Fezandipiti: -Taunt, +Play Rough. -Regigigas runs Leftovers.
Old Gens: The changes below reduces or eliminates (depending on the generation) the likelihood that teams will have multiple Stealth Rock users. -In Gens 4-7, Registeel now runs Thunder Wave on its Staller set; hardcoded to only generate if the team already has a rocker. -In Gens 4-7, Wormadam-Trash now runs Sucker Punch; hardcoded to only generate if the team already has a rocker. -In Gens 5-7, Wormadam-Sandy now runs Sucker Punch; hardcoded to only generate if the team already has a rocker. -In Gens 4-5, Shuckle has been revamped so that it always runs Toxic, Encore, Stealth Rock, and one of Knock Off and Protect; when the team already has a rocker, it doesn't run Stealth Rock and runs both Knock Off and Protect.
-In Gens 4-7, lead Focus Sash no longer generates unless the set contains a hazard or setup move. -In Gen 4-7, Plusle and Minun now run a Life Orb setup set with Nasty Plot, Thunderbolt, HP Ice, and Grass Knot. -In Gens 4-7, Arceus-Poison always runs a Ground coverage move: Earthquake on non-setup and Earth Power on setup. -In Gens 5-7, Chansey's sets have been combined for simplicity. To facilitate this, the Staller role no longer enforces Wish. -In Gens 5-7, non-setup Thundurus now runs Superpower instead of Focus Blast. -In Gens 6-7, Meganium now runs Energy Ball instead of Giga Drain. -In Gens 6-7, Blaziken-Mega now always runs Swords Dance. -In Gens 6-7, Mega Metagross always runs Zen Headbutt, and no longer runs Ice Punch. -In Gens 6-7, Deoxys and Deoxys-Attack no longer run Fire Punch. -In Gens 6-7, Bronzong always runs Earthquake. -In Gens 6-7, Arceus-Fire no longer runs Thunderbolt and Ice Beam, and runs Energy Ball. Its non-Z set always runs Recover. -In Gens 6-7, Bulky Support (Synthesis) Chesnaught no longer runs Leech Seed, and runs Bulk Up and Toxic.
-In Gen 7, Aerodactyl now runs a Z-Flying set with Sky Attack, Hone Claws, Stone Edge, and Earthquake. -In Gen 7, Raticate-Alola now runs a Z-Normal set with Double-Edge, Swords Dance, Knock Off, and Sucker Punch. -In Gen 7, Exeggutor-Alola now runs an AV set with Knock Off. -In Gen 7, Grumpig runs a Gluttony Recycle Calm Mind set with a 50% healing berry. -In Gen 7, Setup Sweeper Comfey can now run Synthesis, which rolls with Giga Drain. -In Gen 7, Nihilego always runs Power Gem.
-In Gen 6, Purugly now runs Wake-up-slap to hit Rock and Steel types. -In Gen 6, Lucario-Mega's physical set runs Adaptability boosted Iron Tail instead of Ice Punch.
-In Gens 4-5, Espeon and Mesprit now run HP Fighting instead of HP Fire. -In Gens 4-5, physical Lucario now runs Stone Edge instead of Ice Punch. -In Gens 4-5, Dusknoir now runs a Staller set like in Gens 6-7, with Shadow Sneak, Toxic, Protect, and Earthquake. Toxic has also been added to its Bulky Attacker set. -In Gen 5, Scolipede no longer runs Quick Feet. -In Gen 5, Regice can now run Thunder Wave and Focus Blast on its Bulky Attacker set.
-In Gen 4, Sunny Day Vileplume always runs HP Fire and no longer runs Synthesis. -In Gen 4, Bellossom can now run Leech Seed. -In Gen 4, Steelix now runs a Staller set with Earthquake, Toxic, Protect, and Iron Head. -In Gen 4, Mantine now runs two sets. Both sets run Surf and Toxic; the first runs RestTalk, and the second HP Flying and Protect. -In Gen 4, Purugly no longer runs Taunt and runs Iron Tail (enabling Choice Band). -In Gen 4, every bulky Rotom forme now runs a RestTalk set.
-In Gen 3, Slaking always runs Hyper Beam, and no longer runs Focus Punch. -In Gen 3, Steelix no longer runs RestTalk; instead, it has a Staller set with Toxic and Protect.
-In Gen 2, Electrode can now run Thunderbolt on its set with screens. -In Gen 2, Jumpluff no longer has its attackless set.
Technical: -In Gens 5-7, High Jump Kick Mienshao will always have odd HP, even when its ability is Regenerator. -In Gens 4-7, Pokemon 4x weak to Rock will have odd HP even if their item is Life Orb or Leftovers.