Some of the best exhibits are large tropical houses and large walk-through aviaries in tropical countries, which show variety of big reptiles and smaller mammals together with birds. For example small kangaroos, iguanas, bats, lemurs, small monkeys, hyrax, large rodents, otters, small ungulates, peccaries etc.
Examples:
Magdeburg zoo tapir house: brazilian tapir, guan, sunbittern, guira cuckoo.
Magdeburg zoo aviary: parma wallabies, budgerigar, many other Australian birds
Tropical hall Kerzers: variety of birds, 3 species of iguana, tortoises, two-toed sloth, leaf-nosed bats. Nearby collared peccaries with spectacled owls.
Madrid: klippspringer, rock hyrax, African birds.
Desert in Arnhem: collared peccary, bighorn sheep, rock squirrel, iguanas, many birds.
Wollemi aviary in Sydney: platypus, echidna, several small wallabies, lizards, birds.
Enchanted Forest in Singapore: fruit bat, ring-tailed lemur, mousedeer, birds.
I like especially if birds are larger species, toucan size or more, and mammals are varied, not just marmosets or sloths which are common in this type.
Interesting how the recent trend of building very big aviaries with ungulate mammals will develop. The cost of large areas of netting is going down.