From left to right:
-Cybran Megalith: Armed with two dual proton cannons, single flak cannon, torpedoes and anti-torpedo flares, Megalith is usually thought of as a sea experimental, especially due to high vantage point of her weapons. Note "her", Megalith can also lay eggs - capsules that turn into certain units.
-Cybran Monkeylord: Rather cheap, the Monkeylord is less resilient than other experimentals, but it's effective nonetheless. Its heavy microwave laser has the highest DPS in the game, and is supplemented with two heavy electron bolters, two defensive SAM launchers and weak Meson Torpedoes. In addition, Monkeylord has personal radar stealth.
-Seraphim Ythotha: Armed with a plethora of various weapons, Ythotha is about as cost-effective as the Monkeylord. On destruction, Ythotha releases a quantum entity that attacks random areas for some time and then expires.
-Aeon Galactic Colossus: Galactic Colossus is one of the largest units in the game. Its only weapons are a Phason Beam generator on its head and two Tractor Beams that drag enemy units close and crush them. GC lacks AA weapons or torps, but its sheer bulk offers it decent protection. It also has an Omni sensor.
-UEF Fatboy: A mobile factory, Fatboy can build UEF land units - the whole roster up to T3. It also has an airpad and a shield dome generator. For fire support, Fatboy carries 12 (4 three-barreled turrets) battleship grade cannons and two riot guns, two AA railguns and torpedoes.