The following list of roles is here to help inspire missions and to help designers find a niche for their vehicle.
Just remember: As cool as your unit is, it needs its place on the battle-field.
Advanced - A fancy way of saying “not quite standard issue yet”. Usually more expensive - Next-Generation equipment.
Armor - Powered-Armor. Units one climbs into whereby one's limbs correspond to those of the unit. Performance differs wildly. Armors incapable of space-use or at least not recommended for it are Terrestrial Powered-Armor. Those capable of complex maneuvers and such are Fighter-Powered-Armor or Advanced Powered-Armor.
Artillery - Chucks heavy weapons fire from afar. And I mean really heavy.
Assault - Designed to get in, unload a lot of weapons and get out. Usually light armor but big weapons. Unlike interceptor, can be heavy and slow or un-maneuverable and fast.
Bomber - Attacks less mobile targets, typically of larger classes. Usually expensive, large and heavy.
Experimental - Second generation. More refined but not mass-produced. Often a little on the weak side but very good at what it is designed to do.
Extension - A part which mounts onto a given unit of sufficient, equal or greater mass than that of the unit. A large booster assembly, Fighter-Extension (the armor becoming the cockpit of a larger disposable unit) or a Powered-Frame for example.
Fighter - Fights other units of its own class. Example: Armor Fighter - Fights other armors. Name infers it is quite agile, borrowing characteristics of star-fighters. Also refers to an agile non-armor unit.
Frame - Refers to a unit similar to a powered-armor but a cockpit may be enclosed separately or the pilot's limbs may not fill those of the machine. “You don't wear it, you climb into it”. Carries larger heavier equipment than Armor and may be directly compatible with armor as an Extension.
X Attack - Optimized for a given environment. Example: Ground attack would be apt at moving through an atmosphere and over the ground in a way which is strategically smart (typically, heavy, slow and quiet). In terms of weapons, this will mean a weapon is especially designed to detonate or penetrate a particular kind of target. Often, much cheaper, lighter and more effective than general-purpose weapons – far more precise.
X Defense - Optimized for defensive roles. Example: A Defense Interceptor would have smart sensors, great engines and great communications and be used as early warning and to make life hell for bombers and heavy armor wings.
General Purpose - “I can do anything! (but I can't do any of them especially well). Specialization breeds strength and multi-purpose units are often humdrum jack of all-trades with lower specs. Can be customized to specialize in a given area. Often standard issue, cheap to produce. Some might say elaborate coffins for NPCs, given the highly strategic nature of “contemporary” warfare.
Imposition - Stops certain classes from functioning effectively, or even at all. ECM/ECCM, mines, communications jamming, etc. Often expensive or complex. Risks disabling your own units. Creates fog of war.
Interceptor - Designed to move across the battle-field quickly. Very quick. Very light armor. Often very cheap to mass-produce.
Naval - Arcane term but it suffices: Basically, means it is dependent on a carrier for fuel and supplies. This usually means it goes back and forth hauling big disposable weapons and fuel like antimatter based kit and runs out quite quickly. Because it is not designed to last as long in the wild, it performs better because it can afford for its parts to be pushed beyond their normal limits so they need replacing on a regular basis because of usage, not damage. This is often necessary because naval units are often front-line units and the extra performance is well worth the maintenance.
Prototype - Built to prove a theory. Often unsafe and unrefined.
Reconnaissance - Surveillance, mapping, monitoring, pattern finding. Two types: (Strategic Reconnaissance - Find out about enemy, don't get seen. Essentially big espionage. Combat Reconnaissance - Monitor the battle, inform friendlies of what's happening. Clear the fog of war.)
Special Issue - Expensive kit given only for specific missions or to pilots/soldiers who earn the use of the equipment by demonstrating their skills. Like naval kit, it is typically high-performance and needs regular maintenance and is more complex. Pilots are expected to work with engineers to maintain their unit and calibrate it. A wild-card, the enemy can be easily confused and become uncoordinated or target-fixated. Ideal decoys - can turn the tide of battle.
Special Operations - Especially modified or suited to a very very specific mission type or environment. For example, unconventional warfare.
Standard Issue - Everyone has one or has access to one. Bog standard kit. Cheap, disposable, reliable. Good for grunts and often available outside the military market (Think AK47).
Stealth - Optimized for sneaking but not attacking directly. Does exactly what it says on the tin.
Strategic - Very very high-precision attacks, like a surgical knife. Block routes, kill key personnel, disable specific systems, etc, avoiding collateral damage at all costs.
Strike - Carries an unusually high-powered payload. Often slow - depend a lot on stealth. Prefix to fighter or bomber.
Support - To be used effectively, this unit must work with others like it in a group or with another class in a synergy. For example: General-Purpose Armor geared for Special Support will guard or augment the capabilities of say, a bomber wing. Together, they are a lot more likely to work effectively.
Test-Bed - Specially built frame to test experimental or prototype parts, hardware or systems. The unit itself aside is technically sound. Test-Beds are often 'watered down' before mass-production and are the final testing stage. Test-beds often see combat, which decide whether they are effective or not.