By leveling up:
* Normal:
* Scratch (Learned at level 1)
* Tackle (Learned at level 5)
* Growl (Learned at level 9)
* Body Slam (Learned at level 13)
* Take Down (Learned at level 17)
* Double-Edge (Learned at level 21)
* Lick (Learned at level 25)
* Yawn (Learned at level 29)
* Rest (Learned at level 33)
* Snore (Learned at level 37)
* Defense Curl (Learned at level 41)
* Rollout (Learned at level 45)
* Crunch (Learned at level 49)
* Facade (Learned at level 53)
* Fighting:
* Body Slam (Learned at level 13)
* Rock:
* Rock Slide (Learned at level 57)
* Ghost:
* Lick (Learned at level 25)
* Dragon:
* Outrage (Learned at level 61)
* Status:
* Growl (Learned at level 9)
* Yawn (Learned at level 29)
* Rest (Learned at level 33)
* Defense Curl (Learned at level 41)
* Amnesia (Learned at level 65)
By TM/HM:
* Normal:
* Return (TM15)
* Frustration (TM16)
* Hidden Power (TM36)
* Soft-Boiled (TM39)
* Substitute (TM45)
* Double-Edge (TM46)
* Facade (TM47)
* Fighting:
* Brick Break (TM28)
* Flying:
* Fly (HM02)
* Poison:
* Toxic (TM06)
* Ground:
* Dig (HM01)
* Earthquake (TM26)
* Rock:
* Rock Slide (TM29)
* Ghost:
* Shadow Claw (TM42)
* Dragon:
* Draco Meteor (TM49)
* Status:
* Thunder Wave (TM09)
* Protect (TM04)
* Thief (TM34)
* Bulk Up (TM39)
* Light Screen (TM43)
* Reflect (TM44)
* Will-O-Wisp (TM48)
* Amnesia (TM46)
By Breeding:
* Normal:
* Belly Drum (From Snorlax)
* Curse (From Snorlax)
* Extreme Speed (From Snorlax)
* Flail (From Snorlax)
* Giga Impact (From Snorlax)
* Last Resort (From Snorlax)
* Swift (From Snorlax)
* Thunder Wave (From Snorlax)
* Whirlwind (From Snorlax)
* Fighting:
* Low Kick (From Snorlax)
* Submission (From Snorlax)
* Flying:
* Aerial Ace (From Snorlax)
* Drill Peck (From Snorlax)
* Poison:
* Sludge Bomb (From Snorlax)
* Ground:
* Mud-Slap (From Snorlax)
* Rock:
* Ancient Power (From Snorlax)
* Rock Tomb (From Snorlax)
* Stone Edge (From Snorlax)
* Ghost:
* Shadow Punch (From Snorlax)
* Dragon:
* Dragon Claw (From Snorlax)
* Dragon Pulse (From Snorlax)
* Steel:
* Iron Head (From Snorlax)
* Status:
* Focus Energy (From Snorlax)
* Guard Swap (From Snorlax)
* Helping Hand (From Snorlax)
* Memento (From Snorlax)
* Quick Guard (From Snorlax)
* Roost (From Snorlax)
* Stealth Rock (From Snorlax)
* Substitute (From Snorlax)
* Swagger (From Snorlax)
* Tailwind (From Snorlax)
* Trick Room (From Snorlax)
Learning a move:
* Leveling up: Some moves are learned automatically as Snorlax levels up.
* TM/HM: Technical Machines (TMs) and Hidden Machines (HMs) are reusable items that teach Pokemon new moves. You can find them in the game world or purchase them from shops.
* Breeding: Certain moves can be passed down from parent Pokemon to their offspring.
Keep in mind:
* Snorlax can learn a variety of moves in LeafGreen.
* Some moves are only available via breeding.
* The movepool is limited to what is available in Generation III.
* Certain moves may be more effective depending on Snorlax's nature and EVs.
This comprehensive guide should help you effectively train your Snorlax in Pokemon LeafGreen.