Inspired by GUDare's "Disposable Heroes" AAR, I'm doing something similar, but with Spire ships. Specifically, I'm playing a self-set scenario in which the Spire must regroup and rebuild their own empire, the humans having been destroyed long ago. To make matters worse, a faction of Spire traitors has sided with the AI (one AI Type is Spire Hammer, the other is Turtle)
My rules: I cannot unlock any upgrades to human tech or unlock and tech not related to the Spire. This means no triangle ships above mk. I, no starships above mk. I (I did accidentally unlock Mk. II Riots, but supposedly those are based on Spire tech so I'll kinda accept that one). If I get things in Zenith caches or ARS, I'll take those but otherwise I won't use anything the Spire wouldn't have. The human triangle ships will only be used on defense, since it'd be a bit too challenging to only use Spire ships.
I've got some stuff on, most importantly Dyson+Hybrids (Never been able to see this combo in action), Fallen Spire, Medium Golems+Spirecraft (The medium versions I find more fun).
Redoing the actual game with Kieth's Seed.