The TBC Newsletter
will keep you periodically up-to-date on what is happening at The Baseball Cube.
There are a selection of Baseball Statistical Feats listed in the Feats section of the site. The feat could be a game (no-hitter, cycle), season (30/30 club, 50 homers) or career accomplishment (3000h,500hr). Most of the feats are for the Major Leagues and use the mostly arbitrary milestones that baseball seems to use. In many cases, I have included players who are close to reaching the milestone but you'll have to check the updated date of the page to see when the stats are "as of". There are also some minor league feats.
I won't list all the feats here because I intend on adding more over time.