Two different Deoxys-speed movesets:
Deoxys-Speed@Sticky Barb
Ability: Pressure
EVs: 4 Hp/252 Atk/252 Spe
Jolly Nature (+Spe, -SpA)
-Knock Off
-Stealth Rock
-Taunt
-Low Kick
For use in gen 9 OU offensive teams, great for setting rocks and also is able to destroy opponents that make contact after a use of knock off. Sticky barb is a great item for a fast, frail Pokémon running knock off due to being able to pass it on to an opponent, and if you time things well, a little luck could let you do some stallerstalling against bulky physical stallers such as araquanid and gliscor. Stealth rock and taunt are what they are, can’t really judge them, and low kick is great for surprising heavier Pokémon like tyranitar.
Deoxys-Speed@Choice Specs
Ability: Pressure
EVs: 4 Hp/252 SpA/252 Spe
Modest Nature (+SpA, -Atk)
-Thunderbolt
-Ice Beam
-Psychic
-Dark Pulse
Simple gen 9 OU specs user, just meant to outspeed pretty much everything and decimate entire teams. Can also function as a late-game cleaner. For a specs user, I think speed form is actually better than attack form due to decent defenses and better speed, not requiring a nature boost to outspeed everything and getting easier foes due to its OU placement, not having to contend with the defensive menaces of Ubers such as ho-oh and necrozma-dawn-wings.