I am trying to think of all the possible ship classes for my space combat game. What are the ones that you know? ie - Fighter, Bomber, Cruiser, Destroyer, Battlecruiser, Battleship, Dreadnought, Super Dreadnought, Mothership, etc.

Frigate, corvette, and carrier (mothership might cover this) spring immediately to mind.

Why are you compiling this list? Do you know the defining traits of each of these craft? What's the difference between a battleship, a destroyer, a dreadnaught and a frigate? I'm sure there is one, but I don't think that the casual gamer would mind much, and applying it to spaceships might entail different definitions of familiar terms.

I recommend that you decide how many classes you'll need, and then name them after you've got them designed. "Tiny, Small, Medium-Small, Medium, Medium-Large, Large and Colossal" should do for starters. Later, you can call them different things.

Generally, any aircraft or naval designation will be suitable, and others, like "Mothership" or "Orbiter" could be considered unique to spacecraft. I always liked the "pursuit" designation of the U.S. Army Air Corps, which became "fighter" when the Air Force was formed (hence the P-51 of WWII became the F-51, etc).

I agree with ironchef - the choices depend more on your gameplay style.

If you have a fast-paced action game, you´ll probably settle in with the lower classes, ignoring the big ones altogether except for mobile scenery. If you´re going the more realistic way you might want to skip the smaller ships altogether and start with the medium sized ones.

Personally I´d start with functions first - i.e. look at what the gameplay requires and define a few classes, then go about naming them or looking for counterparts.

for example:
"medium sized ship with small guns against fighters"
"small, nimble ship with small guns"
"small, slow ships with big weapons against large ships"
"big ship with big guns against big ships"
...

I agree with the others. The differences between a destroyer and a battlecruiser may not be that much, so if you are going to have them both in the game, make sure that they're unique enough to warrant two different classes.

Another one: Gunboat

I'd recommend playing Escape Velocity: Nova some. It's a space exploration/trading/combat game with a huge variety of ships available. Not only are there a reasonably large number of different ship models; there are also different versions of many of those models, which are optimized for different roles. For example:

The default Starbridge ship is a light courier ship. That is, it has a reasonable cargo capacity and a light armament, so it can defend itself somewhat in combat. If you like, you can outfit it with heavier armament so it is more combat capable (you can even sacrifice cargo space for more weaponry). Alternatively, you can sell off all of your armament in favor of cargo space, and create a trader vessel that's perhaps less capacious than the purpose-built cargo ships, but is better-shielded and faster.

In general, the ships that EVN has fall into one of these categories:

Light trader (small, reasonably maneuverable, little space for cargo or weapons, and cheap)
Heavy trader (huge, slow, and expensive, with massive cargo space but little armament)
Light fighter (very fast, but lightly armed and shielded. Serves as an escort or a launched fighter from carriers)
Heavy fighter (not as fast as the light fighter, but better-armed and shielded. Capable of surviving a few passes on the warships. Rarely launched from fighter bays)
Light capital ship (slightly more maneuverable than the light traders, but well-armed and armored. Expensive)
Pocket battleship (a light capital ship that's been optimized for combat; a mixture of heavy armament and maneuverability, but with very little cargo space. Generally the favored ship for players.)
Blockade runner (a light capital ship optimized for cargo; enough space to do profitable and dangerous trade runs, and enough defense to survive them)
Battleship (slow, armed with turrets and missile launchers. Expensive and generally owned by the military)
Cruiser (even slower and better-armed; often equipped with fighter bays for dealing with faster targets)

Now of course, there's a lot of variations on this theme. Some people like sacrificing just about all the space on their light capital ships so they can fit a single fighter bay onto them; it's silly but possible (making a pocket cruiser, I suppose). There's great variety in armament - I prefer going with unlimited-ammo guns and turrets, but some people load up on missiles and torpedos instead. And so on.

I don't think you necessarily want to use "official" terms. For one thing, this is science fiction, so you can more or less make up terms to fit what you want. For another, are your players going to know the difference?

I recommend you play Homeworld or Homeworld 2, if you're looking at how different ships work in a fleet (Homeworld Cataclysm doesn't handle it as well as the other two). Each ship has a very distinct role with specific strengths and weaknesses, that you MUST exploit if you want to win. Fighters are good against other fighters, but get torn to pieces by corvettes. Corvettes aren't bad against other corvettes and are passably good against big ships, but frigates will slaughter them. Frigates don't do too well against fighters and are too flimsey to do a whole lot against bigger ships, but concentrated fire can make it quite possible. Destroyers and cruisers will eat other capital ships for breakfast, but are very vulnerable to fighter/bomber strikes.

This leads to a very complex and tactical game, requiring that you pick your units and fleets carefully. It's also neat because it ensures that the interceptor you developed in the second mission to shoot down enemy interceptors is still a useful unit in the fifteenth mission when you have to take out that horde of bombers before it can cripple your heavy cruiser fleet...

I'd check the way the navy has it set up, because they classify them for the same necessity of usage by design that translates very nicely to space. It's out there, I've no time to link, sorry.

Adventuredesign

BB
CG
CA
DDG
DDA
FFG
FF
FFL
CV
and so on.