I know some of these already...
Reducto - blows objects apart
Relashio - releases firey sparks, useful against Grindylows
Reparo - repairs things
Rictusempra - Causes your opponent to laugh
Riddikulus - spell used against Boggarts
Serpensortia - Summons a serpent
Sonorus - makes your voice louder
Stupefy - stunning spell
Tarantallegra - makes your opponent dance
Waddiwasi - propells small objects
Wingardium Leviosa - makes things fly