Judgement

Edit: Added image, sadly my client doesn't seem to support png animations.

Metronome. The chaos of not knowing what attack is gonna happen is great.

It's why for a fan game I'm still in the planning phases of I plan on having a better version of metronome (name still undecided) that adds all attacking moves, but removes OHKO moves like sheer cold and removes all non-attacking moves. I have plans on making a special option in the intro to make every single pokemon only know this 30PP move.

the first Pokemon game i owned was XD on the GameCube, and like any good kid i overtrained my starter and ignored the rest of my team. i evolved Eevee into Flareon and Fire Blast quickly became my favorite move, killing anything and everything in just one shot. it only has 5 PP, though, so things started getting tough once trainers had six Pokemon. i eventually reached the Ground-type boss and never did get farther than that lmao. but my soft spot for Fire Blast still remains!

Do the legal attacks against emulators and smaller developers count?

...serious now: Surf, Thunderbolt, Flamethrower, Ice Beam. For simple attacks it's the strongest that you can get without sacrificing accuracy. Surf in special, for being an HM that doesn't suck - because I don't bloody want to have a party of Bidoofs dammit. (I'm OK with having two Tropius though - one to fight, another to help.)

I'm a big fan of Tri Attack even though I've never used it myself.

Seismic Toss, but only Charizard from the anime.

Charizard throwing mo'fuckers is awesome every time.

Pound by Mr. Mime.

Dig, but I have a soft spot for Fortify because of its digital reticle animation and the hilarity of exposing you to tons of Metapod spamming it in the early stages of the game.

Lick.

As in Haunter's lick from the OG Anime.

Also rest.

... which is apparently a psychic type move?!

Dream Eater!

Gonna eat your dreams and gain your knowledge

Any two part move like dig or fly.

Gardevoir just being so damn stylish that no one could stand to attack them.

Sing.

They just want us humans to have a good long sleep. Who wouldn't want that?

Destiny bond & explosion

Hyper beam!

Vine Whip, Ivy Seed, and Leech

Tackle

Gigaton Hammer (Tinkaton). Special mention to Triple Arrows (Decidueye.)

Splash. Purely thematic and says “I can’t take you seriously”

Self-Destruct

Gen2's Quick Attack, so zippy.

Close combat, Aura Sphere, Extreme speed, Flamethrower

Curse

Fury swipes on a normal type. I always come in expecting the minimum but sometimes it pops off and gets all 5 hits.

Everything by onion turtle.

Jeez. Maybe cool it for a while.