Pokémon/Pokédex/Ekans

How to Evolve
Ekans evolves at level 22.

TM/HM

 * RB/Y/GS/C/RS/FL: Dig, Double Team, Earthquake, Rest, Strength, Toxic
 * GS/C/RS/FL: Attract, Frustration, Giga Drain, Hidden Power, Protect, Return, Sludge Bomb, Sunny Day, Thief
 * RB/Y: Bide, Body Slam, Double-Edge, Fissure, Mega Drain, Mimic, Rage, Rock Slide, Skull Bash, Substitute, Take Down
 * GS/C: Curse, Endure, Headbutt, Sleep Talk, Snore, Swagger
 * RS/FL: Facade, Iron Tail, Rain Dance, Secret Power, Snatch, Torment

Breeding

 * GS/C/RS/FL: Beat Up, Pursuit, Slam, Spite
 * RS/FL: Spite
 * C: Crunch

Trading Cards

 * Fossil #46 - Ekans
 * Team Rocket #56 - Ekans
 * Gym Challenge #77 - Koga's Ekans
 * Expedition #108 - Ekans
 * EX Sandstorm #64 - Ekans
 * EX Team Rocket Returns #55 - Ekans

Naming
Ekans spelled backwards is Snake, fitting as Ekans is a snake.