Warhammer American War of Independence is a Warhammer AWI variant.
Rules: AWI
Privateers War Rules
Ross Macfarlane has a set of rules for privateer raiding actions during the American Revolution.
DBA For AWI
DBA For AWI is a set of DBA modifications for the American War of Independence.
Charles Sweet’s American Revolution Rules
Here’s a set of classic wargames rules from 1969: Charles Sweet’s American Revolution rules.