This has probably been done before, but anyway here’s a few records that won’t IMHO be broken (maybe tied, but not broken).
Back-to-back no hitters. Accomplished by Johnny Vander Meer, Cincinnati Reds, June 11-15, 1938. Someone could conceivably tie Meer’s record and also throw two straight, but no one is going to throw 3 in a row.
Caught stealing four times in one game. Accomplished by Robby Thompson, San Francisco Giants, June 27, 1986. Yes, it was a 12 inning game, but thrown out 4 times! Absolutely inconceivable that a manager would send a runner a fifth time after said runner had been caught 4 times, so this record is safe.
Two triple plays in one nine inning game. Accomplished by the Minnesota Twins, July 17th, 1990. Yes a team could make a third triple play during one of the remaining 7 innings, but the “set up” is just too unlikely, (two on, no body out).
Back-to-back homers by the same two teammates in one inning. Accomplished by Mike Cameron and Bret Boone, Seattle Mariners, May 2, 2002. In the first inning of the Mariners versus White Sox, Cameron and Boone hit back-to-back home runs. Seattle batted around… and, in the same inning, Cameron and Boone went back-to-back again.To “break” this record, teamates would have to go back-to-back-to-back. That’s just not going to happen in the same inning.
Back-to-back inside-the-park home runs. On August 27, 1977, Toby Harrah and his Rangers teammate Bump Wills hit back-to-back inside-the-park home runs. Again to break this record, you’d have to have 3 players hit consecutive inside-the-park home runs. Not going to happen.
Speaking of Toby Harrah, on June 25, 1976, Harrah became the only shortstop ever to play every inning of a doubleheader and not get a single ball hit to him. Pretty doubtful that will happen again.
Two grand slams in an inning. Accomplished by Fernando Tatis, St. Louis Cardinals, April 23, 1999. You going to tell me some player is going to hit three in an inning?
Any others?