A-Rod could break the HR record, it's plausible, if not probable.
Piazza will break the all-time Catcher HR record sometime this year.
Nobody will ever break the Wins record set by Cy Young.
Nobody will ever break the Losses record set by Cy Young.
Nobody will ever get 5,700 strikeouts again. Prior, if he pitches 20 years, has a possible shot at 5,000. Pedro, if he pitches until he's 45, also has a shot
The Stolen Base record is safe.
Just off the top of my head.