An army of ants/insects
a brood of chickens
a colony of bats
a herd of elephants
a flight of swallows
a flock of birds/sheep
a gaggle of geese
a herd of cattle/buffaloes/elephants
a host of sparrows
a litter of puppies/kittens/cubs
a mob of kangaroos
a nest of ants/rabbits/snakes
a pack of wolves
a pod of dolphins
a plague of insects
a pride of lions
a school of fish
a shoal of fish
a stud of horses
a swarm of bees
a swarm of hornets
a team of oxen/horses
a troop of monkeys
By popular request...
An ambush of tigers
An array of hedgehogs
An army of ants/caterpillars/frogs
An ascension of larks
A badling of ducks
A bale of turtles
A ballet of swans
A band of coyotes/gorillas/jays/men
A barrel of monkeys
A barren of mules
A bask of crocodiles
A battery of barracudas
A bazaar of guillemots
A bed of clams/eels/oysters/snakes
A bevy of quail/roebucks/swans
A bloat of hippos