Pittsburgh Pirates at Philadelphia Phillies

Pittsburgh and Philadelphia faced off in Philadelphia wearing 1933 uniforms.

Photos courtesy of Bill Henderson's MLB Style Guide.

Cincinnati Reds at Pittsburgh Pirates

Special thanks to BurghFan for mentioning this game in the comments:

Pirates and Reds threw back to 1925 on 7/11/93: Google News link 1, link 2, link 3

(Link 1 includes a good photo of Van Slyke before the game and a note on an inside page about how the guy who championed TBTC in the front office had just been fired.)

(A couple of poorly-"printed" action shots, but they're a start.)

Texas Rangers at Milwaukee Brewers

Seattle Mariners at Kansas City Royals

The Royals wore 1969 uniforms, and the Mariners wore 1977 uniforms, both teams first years of playing in the American League.