Moves that Pokémon can't learn but should learn?

[Diamond 97]

I've always thought Inkay and Malamar should have access to Octazooka.

I think Buzzwole should learn Giga Drain. It's UB Absorption. It steals things energy. But can't lean Giga Drain, which is like one the most basic absorbing moves. Giga Drain doesn't benefit it, but it does make sense to learn it.

 

[𒈟Lavemu𒐫]

there's plenty of pokemon clearly flying that can't learn fly, so lets start with that lol

 

[Devalue]

A few random ones:

• Blaziken: High Jump kick. Has a signature kicking move. Jumps 30-story buildings. Cannot jump AND kick.
• Squawkabilly: Sing. Named it after a genre of music (Rockabilly), at least in English.
• Gimmighoul/Gholdengo: Pay Day. Fits the money theme.
• Alolan Marowak: Fiery Dance. Suits its theme more than its stats, admittedly.

 

[ReKoil]

Strange Steam would make sense on Volcanion thematically. Hydro Steam too.
And if Galarian Weezing can emit steam it could also have Steam Eruption in return.

Topsy-Turvy for Hitmontop.
Crustle/Dwebble and maybe other Pokemon that have some sort of object they hide in (or under): Shelter.

Fleur cannon is literally just flower cannon. Could at least give it to the Florges line. Maybe Comfey. Other flower based mons that are mostly flower or have some kind of flower visually present.

Plasma Fists could go to Electivire and the Pawmot line.
Bitter Blade for Aegislash.