By leveling up:
* Scratch: Normal-type move (Learned at level 1)
* Growl: Normal-type move (Learned at level 3)
* Fake Out: Normal-type move (Learned at level 7)
* Fury Swipes: Normal-type move (Learned at level 10)
* Swift: Normal-type move (Learned at level 14)
* Night Slash: Dark-type move (Learned at level 18)
* Sucker Punch: Dark-type move (Learned at level 22)
* Thief: Dark-type move (Learned at level 26)
* Assurance: Dark-type move (Learned at level 30)
* Nasty Plot: Dark-type move (Learned at level 34)
* Snatch: Dark-type move (Learned at level 38)
* Dark Pulse: Dark-type move (Learned at level 42)
By TM/HM:
* Toxic: Poison-type move
* Thunder Wave: Electric-type move
* Will-O-Wisp: Fire-type move
* Protect: Normal-type move
* Substitute: Normal-type move
* Reflect: Psychic-type move
* Light Screen: Psychic-type move
* Shadow Claw: Ghost-type move
* Shadow Sneak: Ghost-type move
* Frustration: Normal-type move
* Return: Normal-type move
* Facade: Normal-type move
* Secret Power: Normal-type move
* Double-Edge: Normal-type move
* Aerial Ace: Flying-type move
* Hidden Power: Varies by individual Pokemon
* Cross Chop: Fighting-type move
* Last Resort: Normal-type move
* Swagger: Normal-type move
* Sleep Talk: Normal-type move
* Brick Break: Fighting-type move
* Low Kick: Fighting-type move
* Rock Tomb: Rock-type move
* Thunderbolt: Electric-type move
* Thunder: Electric-type move
* Flamethrower: Fire-type move
* Fire Blast: Fire-type move
* Ice Beam: Ice-type move
* Blizzard: Ice-type move
* Earth Power: Ground-type move
* Rock Slide: Rock-type move
* Bulldoze: Ground-type move
* Draco Meteor: Dragon-type move
* Outrage: Dragon-type move
* Focus Blast: Fighting-type move
* Energy Ball: Grass-type move
* Shadow Ball: Ghost-type move
* Dazzling Gleam: Fairy-type move
* Dark Void: Dark-type move
* Nasty Plot: Dark-type move
* U-turn: Bug-type move
* Payback: Dark-type move
* Foul Play: Dark-type move
* Trick Room: Psychic-type move
* Swords Dance: Normal-type move
* Extreme Speed: Normal-type move
* Giga Impact: Normal-type move
* Thunderbolt: Electric-type move
* Flamethrower: Fire-type move
* Ice Beam: Ice-type move
* Earth Power: Ground-type move
* Psychic: Psychic-type move
* Dragon Pulse: Dragon-type move
* Hurricane: Flying-type move
* Solar Beam: Grass-type move
* Leaf Storm: Grass-type move
* Sludge Bomb: Poison-type move
* Shadow Ball: Ghost-type move
* Flash Cannon: Steel-type move
* Draining Kiss: Fairy-type move
* Play Rough: Fairy-type move
* Moonblast: Fairy-type move
* Mystical Fire: Fire-type move
* Hex: Ghost-type move
* Psychic: Psychic-type move
* Dark Pulse: Dark-type move
* Shadow Claw: Ghost-type move
By breeding:
* Fake Tears: Dark-type move
* Covet: Normal-type move
* Last Resort: Normal-type move
* Thief: Dark-type move
* Torment: Dark-type move
* Spite: Ghost-type move
* Pursuit: Dark-type move
* Snatch: Dark-type move
* Assist: Normal-type move
By tutor:
* Night Slash: Dark-type move
* Shadow Sneak: Ghost-type move
* Snatch: Dark-type move
* Foul Play: Dark-type move
Remember that the availability of moves can change depending on the game generation and the version of the game you are playing.
It's always best to check a Pokemon database like Bulbapedia or Serebii.net for the most up-to-date information on move learning.