Ever wanted to build a ship bigger than a huge one? I have, and such ships would make combat certainly more interesting, but how would it be balanced, and how would it work with tech speeds? Well, they wouldn't work like most ships, not exactly.
These ships would require administrators, and even bigger than right above huge might need more. They wouldn't act like your average warship but as super weapons that could potentially turn the tide of war but require a whole lot of time and resources to be implemented. These projects would also be heavily affected by spies and counter-espionage, as others would probably want to prioritize your Colossal sized ship in production!
Building a warship of this magnitude would also work very differently. It would require planets linked to the shipyard to funnel production into the project and it being prioritized over everything else (or the project ends up on hold).
Here is my idea of the size names, in order:
Probably not a new idea in the slightest, but with an expansion looming over us I decided to throw this in as it may inspire a future DLC. Hopefully!