Mega Butterfree
Compound Eyes / Tinted Lens
Regenerator
HP: 60
ATK: 45
DEF: 50
115 (+65)
SPA: 90
SPD: 80
120 (+40)
SPE: 70
65 (-5)
BST: 395
495 (+100)
New Moves: Flash Cannon, Stealth Rock
Overview: I thought I'd try to offer a different view to the majority of other people, and try to make a butterfree that contrasts the variety of "fast but frail quiver dance sweeper" megas. Butterfree has always been one of those really strange Pokemon that has a really good and well-rounded support movepool without the base stats, typing or ability to make use of it. This mega-evolution aims to right this issue by fixing all of those issues. Boasting solid all-around bulk, an incredible defensive typing, and an excellent ability that makes this mega evolution very difficult to chip, Mega Butterfree has a number of viable options. With moves like defog, u-turn, roost, toxic, stun spore, sleep powder, whirlwind and now stealth rock, it can act as a glue mon for many teams, with the ability to pivot in and out of many pokemon. Alternatively, thanks to it's newly found bulk, Mega Butterfree can also act as a bulky win-condition with Quiver Dance.
Mega Slowking
Oblivious / Own Tempo / Regenerator
Comatose
HP: 95
ATK: 75
45 (-30)
DEF: 80
110 (+30)
SPA: 100
SPD: 110
140 (+30)
SPE: 30
100 (+70)
BST: 490
590 (+100)
New Moves: Roar, Taunt
Overview: Comaphaze is great lmao. With a buffed speed tier and defenses, Mega Slowking can BS its way through teams with comaphase and entry hazard support using your choice of dragon tail or roar, but also manages to still be a respectable bulky wincon if cheese isn't your thing thanks to its bulk + CM + status immunity
Mega Froslass
Cursed Body / Snow Cloak
Witching Hour (ghost-type steelworker)
HP: 70
ATK: 80
82 (+2)
DEF: 70
60 (-10)
SPA: 80
155 (+55)
SPD: 70
60 (-10)
SPE: 110
153 (+43)
BST: 480
580 (+100)
New Moves: Focus Blast, Moongeist Beam
Overview: Mega Froslass can threaten bulky and more offensive teams alike thanks to its great speed tier (yes its deliberately creeping swellow) and special attack stat, as well as it's adequate movepool. 225 base power moongeist beam hits like a truck, and coverage can pick off whatever may survive it, although mega froslass still remains weak to priority. You might think moongeist beam is weird on something not called Lunala (or smeargle) but this evolution is somewhat night themed so consider it as an emissary / servant of Lunala or something like that