One thing I can recommend against is allowing the players to cast permanency on enlarge person. Especially on monks. I had one player get absolutely out of hand with a high level character (a lycanthropic elven monk that grew to size H and hit for 3d12+21 5 times per round-averaging 3 times the party's 2 paladins' combined damage per round-when he wasn't abusing his size to grapple dragons and swallow opponents whole. Eventually the party's sorcerer gave me the opportunity to nerf the monk with a poorly worded wish-needless to say the monk didn't get the permanent enlargement back).
Things I have had success with in the past include sleep, misdirection, and flaming sphere (makes a great pet).
I'd be hesitant about fly (for one thing it makes items like wings of flying, broom of flying, cape of the bat, etc. perfectly obsolete and needlessly expensive), and at least limit summon monsters to a single summoning made permanent at a time.