>>95942014
>Executor
>Vengeance
>Bellator
>Assertor
>Mandator I/II/III/IV
>Secutor
All of those are sector group HQ-level assets assigned to important High Admirals and above for defending critical infrastructure like orbital shipyards or assigned to personnel outside of the regular chain of command like Vader or Grand-level inquisitors (Jerec)
TL;DR: Anything above ImpStar in size is a statistical anomaly fo the Imperial Fleet