[MCoxon]

I'm a big Feller and Koufax guy. Like Spahn and would add Herb Score who has 2 great Topps base cards.

Feller: 1950B and 1953B are fantastic shots. In lower grades, these are reasonably priced

Koufax: 1963 Fleer is good. The 1965 World Series card is a personal favorite ("Koufax Fans 15"). But for Topps base cards, other than 1956, there aren't a lot of action (though I love the 1965T pose, which you can also find on the 1964 Topps Giants)

Spahn: 1951B is a great shot, though it's stylized. Made the Mike Payne "Top 300 Cards of all time" book

Have you considered Herb Score? Fireballer who's career was cut short but led AL in Ks a few times. His 1956 is great, 1957 is good, and they are both moderately priced

Lastly, Bell Brand and Morrell Meats Koufax shots are some of my favorite cards of all, but expensive and scarce