It is every player who played at least 10 seasons and retired five years ago.
Here's the list, as well as the veterans ballot list: https://www.baseball-reference.com/awards/hof_2020.shtml
Last year, there were 20 first timers. Two were elected (Mariano and Halladay), and two received enough votes to remain on the ballot (Pettitte and Helton). Eleven received no votes at all. Last year was also the last year of eligibility for Fred McGriff, so he will have to wait for the veterans' committee to get another shot.
Every player doesn’t make it. Here is a list of players who meet that criteria and retired In 2014 but aren’t on the ballot.
Mike Adams, Jason Bartlett, Erik Bedard, John Buck, Shawn Camp, Ronny Cedeño, Endy Chavez, Greg Dobbs, Ryan Doumit, Scott Downs, Mark Ellis, Kyle Farnsworth, Frank Francisco, Álex González, Matt Guerrier, Scott Hairston, Koyie Hill, Maicer Izturis, Jason Kubel, Brandon League, Ryan Ludwick, Paul Maholm, John McDonald, Nate McLouth, José Molina, Xavier Nady, Miguel Olivo, Lyle Overbay, Nick Punto, Humberto Quintero, Guillermo Quiroz, Ramón Santiago, Joe Saunders, Marco Scutaro, Josh Willingham and Jamey Wright.