HootHoot, Stantler, Gastly, Drowzee and Poliwag
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I hate to be the bearer of bad news but you can not catch a Pokemon that already knows that as its an TM for soul~silver and a HM for the original silver.
Trade
Nobody knows actually.
bellsprouts can learn it or pikachu (EDIT)** my togepi knows it
I only know 3 moves that makes Pokemon fall asleep. GrassWhistle - Roselia learns it by level up Yawn - Dunsparce learns it by level up Hypnosis - Drowsee knows it when captured in Pokemon Heart gold And Soul silver.