Created my first freeform zoo a few days ago and now finished building it. I chose the small city map - I don't know why but I always liked the maps with buildings, streets and so on (one of my favourite games is SimCity 4 so maybe that's why lol). For a "challange" I chose the lowest amount of money but that wasn't much of a problem to handle honestly. Space management was a bit more of a challange but it worked out quiet well without looking too cramped I think, managed to house 10 different species (and a bird-house which could technically count as 11).
So anyway, I am quiet happy with what I created, used a few mods like those colorful flowers in planter boxes, a few other flower mods and the bridge but besides that I mainly used the vanilla items.
That's the whole zoo.
And here a little closeup.