ZK Porc: All mobile units except builders are disabled.
ZK Sharing: Everyone on a team controls all the team's units, with some number of commanders at the beginning based on playercount (maybe 1 commander for every 4 people, rounded down?). This actually used to be a modoption, but not anymore.
ZK Supercommanders: All commanders go from ulti- to detri- sized from morph levels 1-5, with corresponding HP, range, and damage increases.
ZK Nukespam: Nukes (the missiles) take 30s instead of one minute, along with costing 1/3 what they do now. Nuke silos cost 2500 metal. Antinukes have their normal cost. (yes, this measn that nukes cost less than antinukes overall)
ZK Air Wars: All dedicated anti-air is disabled.
An empty 1x1 map
A giant 24x24 FFA map.
A maze map. Air is disabled, and the area on top of the walls is impassible to discourage jumpy or spider bots to go on them.
ZK Unitspam: Everyone picks a starting (mobile) unit and a builder. They can build defenses and that unit and that builder only. Athenas are disabled unless chosen. Also, the builder and the unit can both be builders (or even the same one, although that would be useless).