There are many spells that work on this site, but there are many that do not as well. I suggest you use common sense when picking a spell to try out. I have some scattered spells on the site from past accounts on the site here that i know have worked. I recommend that if you are looking for a spell, you look under coven spell books and make your selection. A lot of the covens have some nice spells.
Personally I suggest making your own, or taking one from the site and adding some personal flair to it. Obviously transformation spells and the like will not work. I find that the ones that work best for me are bindings. They can be adapted to suit almost any function, and are rather simple.