It really depends on what kinds of moves a Pokémon can learn, and what category those moves fit into.
Say you want to use a fire-type. The vast majority of Fire-type moves are Beauty moves, and while I suppose they would suffice for a Cool or Tough contest, you won't get any Voltage added if you were to use them. And Voltage is a very good thing; if you perform for a judge and completely fill their Voltage, you get a huge bonus added to your score which is almost a guaranteed win in the lower level contests.
Electric-types are very good for Cool contests since almost all Electric moves are Cool moves. Dragons are a great choice too. There are a lot of Normal-typed moves that are Cool (and Tough, too!), Grass has a decent number of them, Flying is alright, and Steel is pretty good too.
Tough moves aren't as plentiful, though there are a good number of them that work with Ground and Rock types. Fighting-types actually take care of both Tough
and Cool.
So really, it depends on what moves you want to teach the Pokémon. Don't forget that many moves can have a special effect in contests, like they can earn extra Appeal if they're performing in a certain order. You can actually combine these effects to quickly build Appeal - for example, if you were performing last, you could use Double Team and that would bump you up to first in your next turn, and then you could use a move that earns extra Appeal for performing first, like Dark Pulse or something. You may have to do some breeding to get moves that you want, however (like if you wanted a Gardevoir or Gallade with Shadow Sneak).
Bulbapedia has categories that separate moves by their corresponding contest category. A list of Cool moves is
here, and the Tough list is
here. It's best to scan the list and maybe have a Pokémon in mind when you're selecting moves, so you can be sure that it can learn all of the moves you're looking at.
I personally use Salamence for Cool contests, and Tyranitar for Tough.