Sticky Web is learned by 15 species by level and 6 by egg

Effect, in PokéAPI's words

“Covers the opposing field, lowering opponents’ Speed by one stage upon switching in.”

Who learns it

21 species in all, 7 games

Scarlet and Violet: 16 species

Species	Method	Level
Galvantula	Level up	Evolve
Grubbin	Level up	25
Charjabug	Level up	29
Vikavolt	Level up	29
Tarountula	Level up	29
Sewaddle	Level up	31
Swadloon	Level up	31
Spidops	Level up	33
Surskit	Level up	38
Kricketune	Level up	44
Spinarak	Level up	47
Ariados	Level up	54
Cutiefly	Egg
Ribombee	Egg
Dewpider	Egg
Araquanid	Egg

Brilliant Diamond and Shining Pearl: 6 species

Species	Method	Level
Masquerain	Level up	1
Surskit	Level up	38
Kricketune	Level up	44
Spinarak	Level up	50
Shuckle	Level up	50
Ariados	Level up	58

Sword and Shield: 10 species

Species	Method	Level
Galvantula	Level up	Evolve, 1
Grubbin	Level up	25
Charjabug	Level up	29
Vikavolt	Level up	29
Slurpuff	Level up	42
Shuckle	Level up	50
Swirlix	Egg
Cutiefly	Egg
Dewpider	Egg
Blipbug	Egg

Ultra Sun and Ultra Moon: 10 species

Species	Method	Level
Galvantula	Level up	Evolve, 1
Shuckle	Level up	1, 53
Sewaddle	Level up	31
Surskit	Level up	38
Kricketune	Level up	44
Spinarak	Level up	50
Ariados	Level up	58
Swirlix	Egg
Cutiefly	Egg
Dewpider	Egg

Sun and Moon: 7 species

Species	Method	Level
Galvantula	Level up	Evolve, 1
Shuckle	Level up	1, 53
Sewaddle	Level up	31
Surskit	Level up	38
Kricketune	Level up	44
Spinarak	Level up	50
Ariados	Level up	58

Omega Ruby and Alpha Sapphire: 7 species

Species	Method	Level
Shuckle	Level up	1, 53
Galvantula	Level up	1, 65
Sewaddle	Level up	31
Surskit	Level up	38
Kricketune	Level up	44
Spinarak	Level up	50
Ariados	Level up	58

X and Y: 7 species

Species	Method	Level
Shuckle	Level up	1, 53
Galvantula	Level up	1, 65
Sewaddle	Level up	31
Kricketune	Level up	44
Surskit	Level up	46
Spinarak	Level up	50
Ariados	Level up	58