My proposed list of changes of mons (Part III):
Empoleon: +Agility
Gives offensive Empoleon sets an extra edge.
Kricketune: +Leech Life, -X-Scissor
Standard Leech Life > X-Scissor; also lets Kricketune preserve its Sash should it get chipped somehow.
Rampardos: +Zen Headbutt
Sheer Force boosted attack that covers Fightings.
Floaztzel: +Switcheroo
Floatzel has often been equipped with a Choice item, and Switcheroo lets Floatzel cripple something it otherwise cannot touch, or just give it freedom in switching moves.
Mega Lopunny: +Fake Out, -ThunderPunch, -Substitute(?), +Power-Up Punch, +Drain Punch(?)
Surprised at the lack of Fake Out since the prospect of both free damage and priority is so great. Iffy at the use of ThunderPunch which doesn't seem to hit very much (even Fire Punch has some merit in taking out Mega Scizor and maybe Forretress). Lack of Baton Pass, Encore, or passive recovery means Substitute just ends up as being kind of 'there'. Power-Up Punch has great potential for MLopunny in Randoms to give it sweeping potential, while Drain Punch is MLopunny's best accurate Fighting STAB, though that's likely less necessary.
Lumineon: -Waterfall
Waterfall doesn't do anything for Lumineon except get in the way of it running Scald.
Abomasnow: +Swords Dance(?)
Mega Abomasnow: +Swords Dance
Being able to boost and sweep with Ice Shard is a huge boon, though I am skeptical on including it on Aboma's moveset since it has so much other moves going on and SD might end up clashing with them. MAbomasnow should definitely run this though, due to its stronger Ice Shard and greater reliance on it.
Rotom-S: -Air Balloon
So I heard that this was non-negotiable or something along those lines, but I still gotta say it: can we just let Balloon Rotom-Fan die? I couldn't care less if you incorporate as much meme sets into these Pokemon as you want, so long as they don't come at the deliberate expense of said Pokemon. Having a useless ability is something to laugh about enough, but why go further in handicapping it by making its item useless as well? I don't see anything being done with Damp Jellicent, nor is Cheri Berry Limber Stunfisk a thing.
Palkia: -Draco Meteor
I get Dialga running this move, because its other STABs in Flash Cannon and Dragon Pulse don't come anywhere close to that power. But Palkia has Spacial Rend and Hydro Pump, both really strong STABs, so Draco Meteor ends up feeling really unnecessary and gets in the way of more useful moves.
Stoutland: +Psychic Fangs
Considering Stout's moves outside of Normal+Dark+Fighting coverage are largely miscellaneous, Psychic Fangs can be an interesting and fairly unique option to broaden its range of targets.
Mega Audino: +Fire Blast
Fire Blast gives MAudino some offensive diversity (especially for 2 attacks MAudino) as opposed to being a sitting duck vs every Steel-type ever.
Whimsicott: +Giga Drain, -Chlorophyll
Would be nice if Whimsicott has access to both its STABs and take better advantage of its defensive typing; would be pretty embarrassing to switch this into Water-types only to lose 1v1 to their Ice Beams. Also can we just get rid of Chlorophyll on this entirely? It hardly ever benefits from it, and I can't tell you how many times I got screwed over because this mon didn't have Prankster to save me from a clean sweep or whatever.
Scrafty: +Poison Jab/Iron Head
Scrafty could appreciate some way to pose a threat to Fairies instead of letting them waltz in freely, though I'm a bit adverse in including more than one since it increases the risk that Scrafty may only have one STAB, which is bad for DD sets.
Sigilyph: +Calm Mind, +Heat Wave, +Psychic, +Psyshock, +Energy Ball, +Dark Pulse, +Air Slash
While I don't particularly mind the existence of Cosmic Power as a set, I do mind it being the only set. Sigilyph has so many great options, especially as a Magic Guard LO attacker, that it seems like a massive waste to delegate it to this DoublePower set that is just so extremely lopsided in effectiveness.
Carracosta: +Liquidation, -Waterfall
In all likelihood, Carracosta is often too slow to try and take advantage of Waterfall's flinch rate, especially on non-Smash sets, so why not settle for the stronger Liquidation? Liquidation even comes with an effect of its own in lowering the foe's Defense, which Costa can immediately take advantage of with Aqua Jet or its other attacks.
Archeops: +Endeavor
I see Head Smash on Archeops' list of moves, but not Stealth Rock or Taunt or the other moves that typically accompany a suicide set (aside from maybe Tailwind), so at the moment, Head Smash just seems like a shaky panic button. Endeavor allows Archeops to take advantage of the recoil, and allows Archeops to maintain high damage in general should it be knocked into Defeatist.
Garbodor: -Rock Blast, +Seed Bomb, +Drain Punch
Rock Blast is a highly outdated attack on Garbo, and it has far better moves to equip itself with, namely Seed Bomb and Drain Punch which cover a decent variety of Pokemon that resist Poison.
Zoroark: +Sludge Bomb
Should definitely update Zoroark's moveset to include this useful anti-Fairy coverage option.
Jellicent: +Hex, -Shadow Ball
Given Jellicent's numerous statusing options, Hex seems like the better choice over Shadow Ball, especially since Jellicent often doesn't aim for immediate damage and has the longevity to make Hex work.
Durant: +Rock Slide, -Stone Edge
Not sure if Stone Edge is wise given Durant's accuracy issues; Rock Slide is likely already sufficient and is more effective with Hone Claws anyway (Rock Slide becomes 72 -> 96 accuracy, while Stone Edge goes 64 -> still shaky 85 accuracy).
Aegislash: +Toxic
Dunno if Aegi really needs this at all; this just lets Aegislash adopt a more defensive style of play. Besides, this move is relevant during Aegi's time in OU and in current Ubers.
Malamar: -Rock Slide, -Substitute, +Rest, +Sleep Talk
Rock Slide doesn't hit enough targets in Randoms to really warrant its use. Meanwhile, Substitute is a pretty poor way for Malamar to evade status in my experience, since it just gets broken way too easily (again, attributing to Random's inefficient EV spreads); a much better way for Malamar to circumvent status is with RestTalk, which enhances its bulky boosting capabilities significantly.
Barbaracle: -Stealth Rock, +X-Scissor
Barbaracle isn't really a good Stealth Rock user in Randoms compared to numerous other options. Instead, Barbaracle can focus on hitting as much Pokemon as possible when sweeping; X-Scissor provides strong and accurate coverage against most of the Grass-types intended to check it.
Heliolisk: -Dark Pulse, +Grass Knot
Dark Pulse doesn't really do much for Heliolisk, whereas Grass Knot provides additional coverage against Grounds, particularly the Water/Ground-types looking to take advantage of Heliolisk's Rain.
Tyrantrum: -Stealth Rock, +Rock Polish
Once again, Tyrantrum is a relatively lackluster Stealth Rock user, and should just focus on crushing opponents instead. Rock Polish provides a significant Speed boost compared to Dragon Dance, allowing Tyrantrum to outrun more foes and easily crush them with its obscenely strong attacks.
Aurorus: -Thunderbolt, -Ancientpower(?), +Blizzard
Thunderbolt is completely useless on Aurorus, and while Ancientpower has slight use against the likes of Articuno, it's debatable on whether it warrants a spot alongside the incredibly useful Earth Power and Freeze-Dry. Being a Snow Warning Pokemon, Aurorus should also definitely have Blizzard as an attacking option; in fact, I realize the lack of Blizzard is probably what makes Ancientpower show up as the sole STAB on Snow Warning Aurorus in numerous cases, which is annoying to say the least
Klefki: +Flash Cannon
Having additional STAB (that doesn't overlap much) in Randoms is never a bad thing, and this allows Klefki to better check a wider variety of potential foes, like Ice-, Rock-, and Fairy-types. It's also accurate.
Trevenat: +Earthquake
This makes Trevenant less linear and predictable, and helps to provide coverage / more damage on Pokemon Trevenant would otherwise struggle to break through. In general, EQ synergizes with Trevenant's Ghost STAB better than its Grass STAB.
Gourgeist: Foul Play
Gourgeist often cannot rely on their own attacks to do much damage bar against super effective targets, so Foul Play serves as a decent middle ground, while also deterring physical setup sweepers from trying to set up in its face.
Noivern: +Super Fang
If you intend to have Noivern run moves like Taunt and Roost, you should probably have some sort of reliable damage dealer to put pressure on its targets in the first place (especially since it has only Air Slash but no Dragon Pulse as reliable STABs on its moveset).
Zygarde: +Substitute, +Coil
Zygarde should have Substitute like its 10% counterpart, especially considering it is the bulkier of the two, meaning Sub still has use even if Zygarde isn't Power Construct. Zygarde's bulk also lends into it being able to use Coil well.
Diancie-Mega: +Power Gem
Special Rock STAB that benefits from Calm Mind.
Decidueye: +Defog, +Nasty Plot, +Energy Ball, +Shadow Ball
Typing and reliable recovery could make it a decent Defog user. Nasty Plot for unpredictability factor and diversify Baton Pass sets.
Primarina: +Hydro Pump, +Energy Ball, +Psychic
More emphasis needs to be placed on Primarina's offensive qualities. Also shaky on Ice Beam since STAB Moonblast covers most of what it does, but I can live with it.
Toucannon: +Bullet Seed, +Brave Bird, +Return, +Boomburst(?), +Overheat(?)
Could use more variety as an immediate attacker, rather than a mon being reliant on setup. Gets Boomburst and Overheat as well, though the existence of Exploud makes me less sold on this idea.
Lycanroc: +Stealth Rock, +Brick Break
Lycanroc-Day should definitely consider SR due to its Speed, and Brick Break adds coverage which Lycanroc desperately needs.
Lycanroc-Midnight: +Brick Break, -Rock Climb(?)
Again, Lycanroc desperately appreciates useful coverage. While Rock Climb doesn't hit anything particularly hard, it's Lycanroc's best option against Fightings and Grounds considering its chance to confuse and inability to miss due to No Guard. Man this Pokemon is really grasping at straws if this move is considered.
Wishiwashi: +Endeavor, +U-turn(?)
Like Archeops, Wishiwashi can resort to Endeavor to maintain damage output should its ability ever kick in. Wishiwashi could also consider using its molasses Speed and titanic bulk to facilitate a slow U-turn into teammates, although this is probably not strongly advised since Wishiwashi needs its health. I also want to know if Figy/Wiki Berry are one of Wishiwashi's primary item choices, as Wishiwashi is one of the biggest proponents of this next to Gluttony Linoone.
Toxapex: +Poison Jab
Additional STAB is always good insurance to have in Randoms.
Araquanid: -Crunch; +Infestation
Crunch is too weak coming from Araquanid, while Infestation coupled with Toxic can start piling up against most bulky Water resists.
Lurantis: +Defog
Not a bad hazard remover either due to typing and bulk, and allows Lurantis to support the team should it struggle to hit the opponent hard.
Shiinotic: +Giga Drain
Additional STAB
Tsareena: +Rapid Spin
Hazard removal
Comfey: +Leech Seed, +Calm Mind(?)
Leech Seed is really nice on this to punish switches, and synergizes well with U-turn / Toxic. Calm Mind is an option to take advantage of those priority Draining Kisses.
Oranguru: +Nature Power
Yet again additional STAB; probably more useful than Thunderbolt even.
Passimian: +U-turn; +Brutal Swing(?)
U-turn is a nice momentum gainer, especially for a Fighting-type. Passimian does get Brutal Swing as Ghost coverage, though it's not strong so Passimian probably wouldn't miss it.
Golisopod: +Leech Life
Having reusable Bug STAB can be pretty important.
Turtonator: +Flamethrower, +Dragon Pulse
Ugh, no wonder Turtonator has been so garbage whenever it shows up. No reliable damage-dealing Fire nor Dragon STAB!? Really?
Dhelmise: +Shadow Claw
Reliable Ghost STAB would be nice.
Kommo-o: +Clanging Scales, +Focus Blast, +Flash Cannon, +Flamethrower, +Autotomize
Special set is mandatory; Clanging Scales is such a good move, and Kommo-o has the coverage to back it up. Autotomize gives the special set cleaning potential.
Tapu Koko: +Grass Knot
Allows Tapu Koko to deal high damage to Ground-types. HP Ice not as necessary as Brave Bird hits Grass-types while Ground-types either take more from Grass Knot or are sufficiently whittled by Nature's Madness (bar Gliscor).
Solgaleo: +Wild Charge
Nails Water-types.
Buzzwole: +Ice Punch, +ThunderPunch, +Roost(?)
Elemental punches add great neutral coverage alongside Buzzwole's STABs. Assuming Buzzwole has other items aside from Choice items, Roost can be an option as well.
Xurkitree: +Tail Glow
Assuming Xurkitree isn't using only Choice items, Tail Glow is the next best move Xurkitree has.