Five former Ivy League players have seen MLB action this season: Brent Suter and Sean Poppen from Harvard, Kyle Hendricks and Cole Sulser from Dartmouth and Jake Cousins from Penn.
According to one source, the NBA currently has one former Ivy League player in Devin Cannady from Princeton
https://basketball.realgm.com/ncaa/conferences/Ivy-League/14/nba-players
As of January 2021, 13 former Ivy League players were in the NFL, according to another source:
https://en.as.com/en/2021/12/10/nfl/1639158921_102106.html