The most common (and best) are PokerTracker and HoldEmManager, which are now made by the same company.
Oh wow I did not know this but it happened way back in 2014 after we Americans had been banned by our government... so it's no wonder I missed it.
Very strange to have one company making two different products that do the identical thing... especially since they've had 6 or 7 years to consolidate them into one.
Back in the good old days before Black Friday happened in 2011, I was running Holdem Manager. It worked okay but the database setup always caused me big problems and I hated dealing with all that crap.
A decade later, I don't run any software, no hand history database and no HUD... but I realize that if I want to get serious about my
poker game, I have to purchase something. Given my past history with HEM, I figured this time I would try Poker Tracker instead. But I downloaded the free trial and once again I had so much trouble getting the database to work properly, I finally just gave up and deleted the free trial, wasting all 30 days of it.
I still have no idea how to resolve my issues with the database crap which never seems to run properly, and therefore I'm afraid to spend the big bucks to purchase anything... so I continue to play at a disadvantage against the serious players who are obviously tracking my play and can see all my stats... but I can't see theirs.
Why are these products so difficult to operate? Nobody else ever seems to have database problems, most people seem to have no problems at all, I never hear anyone else complaining about their HUD not working right. sigh /rant