Base Mode: A facility of some kind.

Component Mode: Part of a combiner, usually as a third altmode, but not always.

Enhancement Mode: A form that attaches to other Cybertronians to enhance them.

Robot Mode: Most Cybertronians primary mode, sometimes an altmode.

Utility Mode: A machine, or some other inanimate object.

Vehicle Mode: The most common Cybertronian altmode.