Comment by Telaneo

At least 4 of those. EA no longer offers any 3rd party games on its own store, but it did.[1] Ubisoft did once upon a time.[2] Not sure if they still do.

Battle.net is still limited to Activision-Blizzard, with a sprinkling of other Microsoft IP following the buyout. Although that might change soon?[3]

[1] https://www.ea.com/ea-pc-third-party-titles-2022

[2] https://gamesbeat.com/ubisoft-welcomes-third-party-games-on-...

[3] https://www.gamedeveloper.com/business/cd-projekt-red-and-bl...