Some prime candidates are listed below.
Capital: Conquest
Cruiser: Apogee, Champion, Gryphon, Heron, Starliner
Destroyer: Condor, Gemini, Phaeton, Valkyrie
Frigate: Dram, Monitor, Lasher, Vigilance
I'd love to see a special faction of independents with alternate versions of the Wayfarer, Gemini, Mule, and Venture. Basically, it's a fleet of the combat freighters, buffed hard. Called the Freedom Freighters. As a play on the word freedom fighters. And with a name like that, they should only appear near Independent colonies during pirate raids, as well as a larger fleet of occasionally hitting hidden pirate bases the month after a raid is over.
All the alternate designs have combat stats befitting actual combat oriented frigates/destroyers/cruisers, at the cost of the cargo and fuel capacity. Straight up wolves in sheep's clothing. So more OP, faster speed, more armor/hull, more base flux distribution and capacity, wider shield arcs, better shield efficiency. Obviously, no civilian systems. All ships have enjoy rugged construction built in and are colored just like normal ships while having the same slots, to throw off the unwary of what a difficult fight might ensue. Gemini needs more than just stats though, so it gets an improved version of it's Reserve deployment system mod, which triples fighters in wing instead of doubles while enjoying it's new combat 90 speed to stay out of harms way. Surprise!
Pirate Champion. Nuff said. Replaces every mount except the large missile with equal sized Ballistic mounts. Changes the system mod to ammo belt feeder. I really like the idea of a ballistic champion, particularly that turret arc.
Pirate Conquest... conquests are the perfect Galleon. Just a color change. Wait a second. There's totally a design space for a special pirate faction.
New special pirate faction. Kanta Kohorts. Fleet found defending Kanta's station. That place is a bit too easy to raid. Kanta needs a special command ship. Kanta's Conquest - Swaps the positions of the first two large ballistics and the front missile, keeping arcs the same, so that makes two forward firing large ballistics (spinal mount) and two side mounted large missiles on 90 degree turrets ... fulfilling the fantasy of nose firing conquests. BTW, I think this to be a weaker setup than normal conquests. But damn that front firing fantasy. Otherwise the rest of KK fleet consists of several Pirate Champions listed above and the rest of the fleet filled out with standard pirate ships (they're all sycophants anyways). Special sauce - the DP size of the fleet is 50+ 50 per pirate base, (so the 4 bases in the core system plus any hidden ones that pop up).
Vigilance - The thing missing for Vigilance to see more use is a specific difficult to pull off Ai behavior. It needs to hide behind larger ships and poke it's head out to fire occasionally. So instead of that behavior, how about a system to negate the need to do that. Vigilance Eternal model. Has system to dump a portion of it's flux to a nearby friendly ship with the least flux buildup. It can use this frequently, but % transferred is based on how empty the target capacitor is, so it works best when transferred to ships with an empty capacitor, and nothing is transferred if every ship near it is at high flux This will allow it to live as close escort to a battleship in high dp battles and not get randomly obliterated by a stray shot.
Heron. It's a pure carrier so it's hard to find a new direction for without totally recreating it. So here's a recreation that doesn't use anything new. Heron(TT) Tri-Tachion edition. 3 wings of terminator drones and special system replaced with Terminate Sequence. Flux and shields buffed to high-tech standards.