A Clone Legion is a division or group inside a Clone Corps. Normally, they are under the command with a Jedi General Some notable Clone Legions are: The 501st Legion, 212th Attack Battalion, and the 104th Battalion.
In Legends, the 111th Clone Corps survived Order 66, due to a signal failure. One of their Clone Legions was The 808th Ground Force Battalion. They fought the Empire, taking on the name The Clone Resistance, but eventually falling to the never-ending might of the Empire. Immediately after their defeat, the Rebellion became a major threat to the Empire.
<ref name="Star Wars: The Clone Wars">[[Star Wars: The Clone Wars|''Star Wars'': ''The Clone Wars'']]</ref>