The 7 Warlords of the Sea

The Seven Warlords of the Sea are pirates that aren't hunted by the World Government in return for their servitude, but it's not unheard of for a Warlord to abuse this privilege by working against the World Government secretly. The Seven Warlords are usually dangerous pirates with high bounties that were frozen when they joined. The lower a frozen bounty is, the more the World Government saw them as a threat that could develop later on.

The Timber Lord

 * A Warlord with a tree based Devil Fruit and had a frozen bounty of 100 Million. Even still, he was one of the weaker Warlords.

Chip

 * Chip claimed he was a Warlord, and certainly wasn't weak, but given the fact that he has a mischievous streak and none of the Marines who searched his casino mentioned his status, it's currently unknown if he was a Warlord.