TM26 (item)

Effects

TM26 teaches a move to a compatible Pokémon. TM26 is:

Red/Blue	Silph Co.
Gold/Silver	Victory Road
Ruby/Sapphire	Seafloor Cavern (final room with Groudon/Kyogre) (Pickup ability in Emerald, 1% chance at level 91-100)
FireRed/LeafGreen	Viridian City (Gym - defeat Giovanni)
Diamond/Pearl	Wayward Cave (secret entrance under Cycling Road - requires Cut, Strength and Bicycle) Battle Park (80 BP) (Pickup ability, 1% chance at level 91-100)
HeartGold/SoulSilver	Victory Road Battle Frontier (80 BP) (Pickup ability, 1% chance at level 91-100)
Black/White	Relic Castle
Black 2/White 2	Route 15 (southeast)
X/Y	Route 22 (Détourner Way)
O.Ruby/A.Sapphire	Seafloor Cavern
Sun/Moon	Resolution Cave (middle, requires Tauros Charge)
Ultra Sun/Ultra Moon	Resolution Cave (middle, requires Tauros Charge)
L.G. Pikachu/L.G. Eevee	Celadon City (across pond)
Sword/Shield	Galar Mine

Ruby/Sapphire Emerald	Causes a quake that has no effect on flying foes.
FireRed/LeafGreen	An earthquake that strikes all POKéMON in battle excluding the user.
Diamond/Pearl Platinum HeartGold/SoulSilver	The user sets off an earthquake that hits all the Pokémon in the battle.
Black/White Black 2/White 2	The user sets off an earthquake that strikes every Pokémon around it.
X/Y O.Ruby/A.Sapphire	The user sets off an earthquake that strikes every Pokémon around it.
Sun/Moon Ultra Sun/Ultra Moon	The user sets off an earthquake that strikes every Pokémon around it.
Sword/Shield	The user frightens the target with a scary face to harshly lower its Speed stat.