In 1957 Ted Williams set a unique record of hitting the most consecutive home runs over the course of four games (September 17, 20, 21, 22) with four — all the other plate appearances during those games were bases on balls (walks).
Only two pinch hitters in Major League history have had three pinch-hit home runs in consecutive at-bats: Lee Lacy on May 2, 6, 17, 1978, and Del Unser on June 30, July 5, 10, 1979.
The most consecutive home runs ever hit during a single game of play is four held by Mike Cameron, Rocky Colavito, Carlos Delgado, Lou Gehrig, Bobby Lowe and Mike Schmidt.