Tier 2 Kbots
One of the few fast raiding units the Core has, the Pyro is a reasonably quicker Kbot armed with a short-range flamethrower. The flamethrower is deadly against groups of units and against groups of buildings. The Pyro isn't really cut out for direct assaults, however. It has few hitpoints and the flamethrower's range is very short. The Pyro tends to be something of an odd duck, then, since it doesn't fit in with the typical Core strategy of slow domination.
One of Core's most iconic units, the Can is a huge, fat and heavily armored Kbot with an extremely powerful laser. It is a very, very slow unit, but once it arrives on the battlefield it is hard to stop. The Can is best when attacking positions that are on flat terrain as its laser is a direct-fire weapon and the can's slow movements can be easily confused by obstacles.
The Roach is a suicide bomb unit. Its usefulness is limited to the obvious - it blows stuff up. The Roach is slow by itself, so they are best if loaded up into a transport like a Valkyrie or a Envoy.
The Kbot version of a radar jammer, the Spectre is capable of completely disguising your units from enemy radar. It is very useful when combined with Cans and Sumos because it can actually give these slow-moving units an element of surprise. It also can be used to hide your base from radar if you're being hit with long-range artillery fire.
A fast attack Kbot, the Freaker doesn't really fit in with the Core's unit lineup. It isn't well armored, but it is fast enough to avoid most danger. It can be used to penetrate enemy lines if there appears to be a weakness. The Freakers can then go berserk on undefended structures. It is essentially worthless in direct combat.
An interesting long-range mortar Kbot, the Morty is meant to bombard enemy positions from afar. It isn't very well armored, but it is extremely effective at what it is meant to do. In fact it is probably the best mobile artillery unit in the entire game. There are other artillery units which do more damage or have longer ranges, but they also are very expensive. The Morty is actually affordable, so you can mass a useful number of them early in the game.
The opposite of the Spectre, the Voyeur is a mobile radar Kbot. It can be useful if your attacking a base outside of your normal radar range, but radar buildings are so cheap and plentiful in Total Annihilation that you won't end up building these often.
The Sumo is basically what you get if you take the Can and say "Gee, this is great, but it just isn't tough enough." The Sumo is the deadliest land unit in the entire game besides the Krogoth. It has tons of health and is armed with a massive laser capable of killing most units in just a few hits. However, the Sumo is also the slowest land unit in the game. It is so slow that attacking with Sumos is almost impossible unless you are playing a small map.
The Gimp is a medium Kbot armed with a fairly effective laser. It isn't fast or tough or powerful, but it does have a party trick - it can go underwater. But to be honest, you're probably better off building normal Kbots and using transports.
Yes, this unit looks just like your Commander. It moves and acts just like a Commander would, although it doesn't have the same abilities. It is used solely to trick enemies into attacking the wrong unit. It is well worth building a few if you have the chance, particularly if the Assassination victory condition is being used.
This Kbot can actually resurrect units that have died in battle. Just direct the Kbot over to the hunk of metal which once was a unit and the Resurrection Kbot will do its magic. The Resurrection Kbot is awesome to have on defense because it can slowly bring your defensive units which died back to life. On offensive, however, it is a bit less useful. The Resurrection Kbot itself isn't tough and it takes some time for it to resurrect a unit.