Massive structures like the ones in the title are, I’m sure, difficult to implement, but I think it would be a huge boon to gameplay.
Each structure could be fenced in and locked up, and opening them could allow for new monsters to be spawned in the world.
Zoos, for example, could have stuff like lions, elephants, tigers, komodo dragons, etc., both living and zombified versions, depending on how the structure generates. Once you throw the cage-unlock switch or whatever, animals from the zoo could not only escape, but start breeding in the wild. Now, a breeding system would be a bit overly complex, so I’d suggest that freeing the zoo creatures would just result in things like lion cubs and baby elephants being spawned after a while.
They could grow up and spread, somewhat akin to the already-implemented fungus critters.
Additionally, I’d like to see unique pelts for different animals, just because it’d be cool to have like, a bearskin rug on my floor, or a lion pelt on my mantle. Some sort of big game hunting system would be rad.
The dinosaur parks, which I feel already have canonical potential because of things like raptor serum, could work in much the same way as zoos, except with dinosaurs being released instead. Both zoos and dinosaur parks could have tranquilizer guns in them, so you could knock out animals in game, and possibly start your own zoo/lab/private hunting reserve.
Fairgrounds could be suuuper terrifying, as they’d allow for things like zombie clowns and sideshow zombies. Apart from that, maybe some useful mechanical bits from the rides, and some junkfood from the stands.
Lemme know what you think!