The Dallas Cowboys and San Francisco 49ers have been tangentially linked for decades as two of the most valuable and internationally-recognized franchises in the NFL. That rivalry peaked in the 90s with the Cowboys defeating the 49ers in the 1992 and 1993 NFC Championships, then San Francisco getting revenge in 1994. The winner of those conference title games went on to win the Super Bowl in each of those seasons.
Stars like Deion Sanders ended up playing for both (the Niners in 1994, then the Cowboys from 1995-1999), a tradition that continued with Terrell Owens (SF from 1996-2003, then Dallas from 2006-2008) and could be realized once again with the current free agent status of receiver Dez Bryant.