TM66

TMs vary between generations; however, TMs numbered 51 to 92 were not added until Generation IV; TMs numbered 61 to 100 do not exist in Pokémon: Let's Go, Pikachu! and Let's Go, Eevee!.

TM66 is:

TM66 MT66 CT66 MT66 わざマシン66 招式学习器６６