Great question.....if for big game:
1) 270 win or 270 WSM. Deer and Antelope sized game...does well as a varmint and predator round too..
2) 300 Win Mag or 7mm RM. Elk, Moose
3) 375 Grizzly, Moose, Bison, Big bears,,,also this is the minimum caliber for African dangerous game.
There is plenty...