Some good first answers/guesses, but there's still plenty more to go.
Thats the Fallout 3 directional minimap thing in the bottom left.
Minecraft quick select tool bar
Correct.
Xcom 2 targeting info in the middle.
I'm pretty sure it's from XCOM: Enemy Unknown.
Top info bar is Civilization (4?)
Civ 5.
Witcher 3 Amulet and health bar upper mid left.
The Witcher 2. 3 is slightly more fancy.
Stellaris Fleet info in the middle overlaying the Xcom target bar, I think.
It doesn't look like anything from Stellaris as far as I know, but I wouldn't know what else it could be.
Cities Skylines info bar on the far left
Correct.
GTA 3-ish looking upper right corner of money, time and MP5. Just naming one
I'm pretty sure that's from GTA: San Andreas.
I thought it would be the Fallout 3 VATS since the bottom left is also Fallout 3, but it turns out that VATS looks exactly the same in both games. However, the Radscorpion health bar slightly above the middle of the screen is from Fallout 4, so the VATS is probably as well.
Correct (as far as I'm aware the crosshair is the same for Portal and Portal 2).
Lego Star Wars active character portrait
Specifically LEGO Star Wars: The Complete Saga.
Team Fortress in the lower right?
Correct. As well as the blue and red in the top middle of the screen, including overtime counter.
i see terraria (the blue squares at the top)
Correct.
eurotrucker simulator for the rear view mirror?
I think so.
battlefield 2042 for the map.
Do you mean the mini-map in the bottom right? Because as far as I can see Battlefield 2042's mini-map does not feature a grid. I have no idea what it could be though.