This is actually "Fall Further" territory for me, but it still represented a very memorable series of opportunities and other turns of events when playing a Malakim game with Decius, whose prime difference between base FFH and FF is having the "Conqueror" trait, which really is a rebranding of Elohim "tolerance." That is, you conquer a city, congrats you can build their UBs, UUs, etc.
I forget what the map type was, but whatever it was I definitely loaded it up with "interesting" AI civs, really with the notion I'd love to get my mitts on their UBs and UUs.
Neighbours were the Balseraphs and the Svarts. Which meant before too awfully long I had Balseraph cities of my own, defending a bottleneck from some lizardfolk Cualli to the North... and Svart cities which I took on my Western border, starting to churn out Recon focussed stuff. Only had sea elsewhere so I sort of had a pure Malakim heartland with captured settlements from two different civs on the perimeter.
Eventually I also had Chalid with some decent command promotions, so not only could I go through the effort of building another civ's units, occasionally I'd capture some ready made and highly promoted, fair and square. This ended up happening with a lot of uppity lizards from the North who'd occasionally try and brave the bottleneck.
Anyhow, what probably made it memorable is I just kept collecting some very frightening mixed armies. Much like when you have cities specialize in different kinds of units (i.e., this is my Altar city churning out priests, here's my melee production centre), in this case, the "conquered civ" cities ended up making for some pretty natural choices... like Svarts built Nox Noctis, which I stole from them, and made into a decent training ground for assassins. Same with the Balseraph cities, they were kind of useless except as a great place to build Mimics, who'd soak up all kinds of promotions from going into battle with the Svarts and the Cualli. Again, when you mixed in the forces of three races, and supplemented it further with some "exotic" captured specimens like some wacky Cualli priests who had some kind of shadow magic (Priests of Agurron? Forget), you'd end up with some very, very versatile stacks of doom, basically like a "greatest hits" compilation (and always blanketed in Valor spells by Chalid, noting "Valor" wears off after a short duration in FF), good times.