In the earlier Pokemon games, players had to use an HM to perform certain tasks that also doubled as moves.
A concept for the best HM Slave : r/PokemonUnite
20 Best Hoenn HM Slaves For Pokémon Ruby, Sapphire & Emerald (And ORAS) – FandomSpot
HM slave : r/pokemon
Talk:TMs and HMs - Pokemon Black 2 and White 2 Guide - IGN
Pokemon Emerald: The 16 Best Hoenn HM Mules
Top 10 HM Slaves in Pokémon - LevelSkip
Types of pokemon in a nuzlocke #3. The HM slave : r/nuzlocke
Top 10 HM Slaves in Pokémon - LevelSkip
Pokemon Red (I patched the game to give myself a random starter as well as to allow my hm slave to learn every hm) : r/PokemonHallOfFame
NO MORE HM SLAVES - Pokémon Infinite Fusion [#29][BLIND] PC Let's Play
Top 10 Mega Evolutions For The Diamond And Pearl Remakes
Has anyone of you beat frlg or any other Pokemon game with less than 6 Pokemon? I beat leaf green once with 5 Pokemon (4 if excluding hm slave sandshrew). : r/PokemonFireRed
BW Tips and Tricks - Smogon University