I guess this was supposed to be an answer to your previous thread (you can just add a reply by scrolling down to the textbar and finish with "Post reply". But to answer your question:
RIght now I've 21 games installed on Steam and 3 from Xbox Gamepass, so 24 in total.
I have about 30 games installed, filling about 70% of a 1tb SSD. Rainbow Six: Siege and Red Dead Redemption 2 are taking up a good portion of that, haha.
Probably 20 or so. The games I'm currently not playing but don't want to uninstall I move to my traditional hard drives, the games I'm currently playing stay on the SSD's.
I have too many games installed for no other reason that "maybe I will replay it AGAIN soon" aka whole Dark Souls series. And few for co-op fun with friends now and then.
Jeez, 28 games installed. I really need to clean some junk out. A lot of those are tiny by today's standards, though, like the original XCOM and Master of Orion 2.
As for how they fit - most aren't installed to SSD and my main drive is about 3.6TB after formatting. I don't think it's even half full.
Oof. I have 69 games on Steam installed, 11 on GOG, 2 on Epic, 1 on Bethesda.Net, and maybe 10 indies that either came direct or from itch.io. Plus Magic: The Gathering—Arena and Star Citizen. So that's 95?
All that's taking up about 900GB of an SSD. I definitely recommend getting an SSD.
77 Steam Games on my main OS (Fedora Linux). About 10 - 20 GoG on a Win10 Virtual Machine I run inside Fedora. They are the D&D SSI/Gold Box exclusives and the classic Ultima games. I'm moving those over to my host OS, and off the Windows partition, as soon as I get around to it.
How do I do it? I have 2 1TB SSD (an EVO 850 and 860) that I have configured as a single logical volume so I have 1.8TB storage. Very large games like Dragon Quest XI and ESO get removed if I don't play them for a while. While I'm not worried about my SSD lifespan I try and minimize deleting and downloading large games often.