First, the Brimstone.

Featuring sustianed rate of fire, armored fighting compartments, and rugged shape that kinda looks like a demolition charge.
I've tested this ship against the "Terror" head-on, while losing it's entire fore to the Terror's first salvo, the Brimstone could still defeat it with constant missile fire.
And another experimental tileable design, the Firebat, inspired by the "Diagon Death Dealer".

Honestly this one is a bit ugly, but works just fine.