Common Mammals:
* Humans
* Dogs
* Cats
* Horses
* Cows
* Pigs
* Sheep
* Goats
* Monkeys
* Elephants
* Whales
* Dolphins
* Bats
* Kangaroos
* Rabbits
* Mice
* Rats
* Squirrels
Less Common Mammals:
* Platypuses (lay eggs but are still mammals)
* Echidnas (lay eggs but are still mammals)
* Opossums
* Armadillos
* Sloths
* Anteaters
* Bears
* Lions
* Tigers
* Cheetahs
* Giraffes
* Zebras
* Hippopotamus
* Rhinoceros
This is not an exhaustive list, but it gives you a good idea of the wide variety of animals that are born alive.