Don't know any spell's? here are a few that you can use:
Accio (summoning charm)
Alohamora (opens/unbinds)
Arania Exume (helps when attacking giant spiders)
Avis (spell used to make birds fly out of one's wand)
Diffindo (spell used to cause things to split apart)
Engorgio (makes things larger)
Ennervate (used to revive someone who has been stunned)
Evanesco (make dissapear)
Expelliarmus (disarming spell)
Ferula (banages wrap feet of opponant)
Impedimenta (used to slow down attackers)
Impervious (repels water)
Locomortor Mortis (leg lock spell)
Lumos (used to make a wand emit light)
Nox (cancels out Lumos)
Occulus Repairo (fixes Glasses/vision)
Orchideous (makes flowers spring out of the tip of a wand)
Obliviate (erases Memory)**
Quietus (cancels out "Sonorus")
Reducio (shrinking charm)
Rictusempra (tickling charm)*
Serpensortis (produces a snake)
Sonorous (spell used to magnify a voice like a loudspeaker)
Scourgify (cleans up a mess)
Stupefy (spell used to make someone unconscious)
Tarantallegra (dance uncontrollably)
Wingardium leviosa (spell used to make something/someone float.)
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I'm posting these for general knowledge and to get things moving again.
*My fave spell. I'm really good at it so be warned.
** I don't highly reccomend this spell seeing as it may turn out for the worst. but IF you use it right then it should be okay. Please state what/how much memory is being erased when using this spell. no fair using it and saying your opponent forget all magic spells and therfore you win.

Not acceptable.