Bell P-39 Aircobra. Engine is behind pilot which caused problems for pilots unfamiliar with the turning characteristics. Many were sold to Russia in WWII.
Douglass SBD Dauntless, made famous at Midway. Nicknamed "Slow But Deadly", the rugged Dauntless had the lowest loss ratio of any U.S. combat airplane. How rugged? Pilot Stanley Vejtasa was jumped by 3 Zeros. He shot down 2 and rammed the last one head on, cutting off its wing, then flew home to the carrier without incident. This was a bomber-not designed to dogfight!
Carrier based Douglas A1 Skyraider, used in Vietnam primarily for ground support. Considering it's fighter plane size, it could carry an amazing variety and weight of ordinance-TWICE as much as an 8th Air Force B-17! It was hardy, reliable, and loved by its pilots.