These are some features I noticed, looking through Foxx’s game log. In 1938, Foxx achieved each stop from 1 to 8 RBIs in a game, which I could see being a feat no one else has achieved in MLB history. Foxx twice drove in 6 runs in one game, drove in 4 runs in six games, and closed out the 149-game season with 7 RBIs vs. the Yankees on October 1. He had a streak of 14 RBIs over 5 games, and a streak of 13 RBIs in 4 games. He drew 6 walks in one game, vs. the Browns on June 16.
He did these things without the benefit of Ted Williams: the Red Sox who finished second to Foxx’s 175 RBIs was Pinky Higgins with 106, and second behind Foxx’s 50 homers was Joe Cronin with 17.