14: Mercury Capri 5.0
Released in 1968, the Mercury Capri was the corporate cousin of the Ford Mustang. With the 5.0 trim level, the Mercury Capri was basically a bubble-back Ford Mustang. Many enthusiasts don’t realize this and the Capri is slightly undervalued because of it. But with the Mustang 5.0 becoming scarcer, there has never been a better time to purchase one (via Hemmings).
The styling is similar to the Mustang, and most parts are interchangeable. There is also a massive aftermarket community where you can find any customization that you want. On top of all that, the 5.0 engine is seemingly bulletproof when it comes to reliability. The Capri is probably one of the most underrated muscle cars around and will rise in price soon.