I worded that poorly. I meant, "An enchantment that you might cast on EITHER your own creatures or your opponent's creatures." That is, double edged enchantments you might use to help your own stuff or hurt your opponent's.
For example, nullify goes both on your own creatures to prevent curses, and also on the other guy's to prevent heals. Or, to use a curse example, you might place Death Link on your own regenerating creature (or to knock off Sleep), or you might place it on an opponent's creature to do DoT.
So, yeah, Nullify, Death Link, Turn To Stone, maybe. It's a limited category, but troublesome because it's forbidden to have two enchantments with the same name on a single creature (regardless of controller) but there's no way to know that this has happened until one flips.
Personally, I favor an erratum to allow only one copy of an enchantment with a given name, per controller (or team in cases of more than 2 players).