Pokémon/Pokédex/Gengar

TM/HM

 * RB/Y/GS/C/RS/FL: Double Team, Hyper Beam, Psychic, Rest, Strength, Thunder, Toxic
 * RB/Y/C/RS/FL: Thunderbolt
 * RB/Y/GS/C: Dream Eater
 * GS/C/RS/FL: Attract, Frustration, Giga Drain, Hidden Power, Protect, Rain Dance, Return, Rock Smash, Shadow Ball, Sunny Day, Thief
 * RB/Y: Bide, Body Slam, Counter, Double-Edge, Explosion, Mega Drain, Mega Kick, Mega Punch, Metronome, Mimic, Psywave, Rage, Seismic Toss, Selfdestruct, Skull Bash, Submission, Substitute, Take Down
 * GS/C: Curse, Dynamicpunch, Endure, Fire Punch, Headbutt, Ice Punch, Nightmare, Psych Up, Sleep Talk, Snore, Swagger, Thunderpunch, Zap Cannon
 * RS/FL: Brick Break, Facade, Focus Punch, Secret Power, Skill Swap, Sludge Bomb, Snatch, Taunt, Torment

Evolution

 * GS/C/RS/FL: Haze, Perish Song, Psywave
 * RS/FL: Astonish, Explosion, Grudge, Will-O-Wisp

Trading Cards

 * Fossil #5 - Gengar
 * Fossil #20 - Gengar
 * Gym Heroes #14 - Sabrina's Gengar
 * Gym Challenge #29 - Sabrina's Gengar
 * Neo Destiny #6 - Dark Gengar
 * Expedition #13 - Gengar
 * Expedition #48 - Gengar
 * Skyridge #H9 - Gengar
 * Skyridge #10 - Gengar
 * EX FireRed & LeafGreen #108 - Gengar EX