ViZar
your toast is burned
New Pokémon Name: Belle Pikachu
Stat Changes: 90/75/90/75/90/100 (520)
Typing Changes:
Ability Changes: Misty Terrain
Movepool Additions (If Any): Court Change, Heal Bell, Milk Drink, Icicle Crash
What Separates it from Other Forms: Belle provides team support with Court Change, Misty Terrain and Heal Bell. Of course it also has Wish for teammates that lack recovery.
New Pokémon Name: PhD Pikachu
Stat Changes: 90/90/75/90/75/100 (520)
Typing Changes:
Ability Changes: Regenerator
Movepool Additions (If Any): Corrosive Gas, Sludge Bomb, Poison Jab, Gunk Shot, Electric Terrain
What Separates it from Other Forms: PhD is an offensive Pokémon with great longevity thanks to Regenerator.
Pop Star Cosplay
New Pokémon Name: Pop Star Pikachu
Stat Changes: 90/65/85/95/85/100 (530)
Typing Changes:
Ability Changes: Pixilate
Movepool Additions (If Any): Hyper Voice, Moonblast, Play Rough, Draining Kiss
What Separates it from Other Forms: Pop Star is designed to be a wallbreaker due to Pixilate boosted Hyper Voices. It can't abuse Pixilate Extreme Speed well, but I think that's a good thing.
New Pokémon Name: Libre Pikachu
Stat Changes: 90/95/85/65/85/100 (520)
Typing Changes:
Ability Changes: Guts
Movepool Additions (If Any): Close Combat, Aura Sphere, Flying Press, Bulk Up
What Separates it from Other Forms: Libre is the same Pop Star, but as a physical Fighting-type, that isn't bothered by burn thanks to Guts.
Rock Star Cosplay
New Pokémon Name:
Stat Changes: 90/100/65/100/65/100 (430)
Typing Changes:
Ability Changes: Punk Rock
Movepool Additions (If Any): Boomburst, Overdrive, Stone Edge, Power Gem, Head Smash, Meteor Mash
What Separates it from Other Forms: Rock Star is a mixed attacker with good options on each site. Physical sets have high basepower moves like Volt Tackle and Head Smash with Extreme Speed, while special sets have Punk Rock boosted Boomburst and Overdrive.
Site Note: These Pikachu don't get the Light Ball boost.