There are couple of diablo 3 caps after 1.04 patch. I will list down a couple, will add in more as time goes by.
Movement Speed – Cap at 25% maximum
Bonus to Gold/Globe radius – Cap at 49 yards maximum
Magic Find/Gold Find – Cap at 300% maximum*
For MF & GF, there’s something special about it, the 300% maximum caps is only applicable to your own equipments + paragon bonus. This means that you can get higher than 300%.
2) Nephalem Valor, each NV gives you 15%, maximum 5 NV will give you 75%.
In short, you probably can get near 400% total Magic Find in a solo game!