Perfect Dark.

Despite its problems, Flight Simulator by a mile. The rest is all in decline. Well maybe not Forza Horizon, 4 was still fun.

I forgot about Age of Empires; it's definitely up there as well, the first two games in that series were some of my favourite games growing up, absolute classics.

If Doom is now considered an MS franchise *(is it?) with the purchase of Besthesda that would as frontrunner as well; the original and the 2016 reboot would both make my top 20 games of all time, and II and III were good as well.

Gears. Kinda stumbled with Gears Judgment and Gears 4 but it's been a favorite for over a decade, now. That over the top feel and the sense of camaraderie just can't be beat.

As someone else implied here, Age of Empires is kind of dead nowadays but Age of Empires II is one of my favorite games, so I can't discard it so easily. Gears of War games come close, I love their multiplayer sides.

Back in the day: Age of Empires

Today: Gears

That title belongs to Mario Kart.

But as far as boring old regular cars racing goes, I know Forza is one of the best out there. Most people call regular cars racing, a racing sim. Not sure if it's the best racing simulation franchise though, because I'm not into racing sims. I find racing sims as boring as farming simulator 2020, or sports team manager simulator, or watching paint dry simulator. It doesn't help that the Forza Franchise gets a new game almost every single year with what looks to be minimal improvements.

We don't know if Bethesda's IP will really become exclusive, but if they do then the answer for me will be Fallout.

As far as franchises that have been and currently are exclusive. Hmm, probably Halo.

Halo. 

I don't really like the series new titles, but Halo 1 through and including Reach stand as some of my favorite games of all time. I think it's very sad that, in part because of the kind of mass somewhat-toxic audience they drew in originally, and also because of the reception of newer titles, the series is often looked upon as "never having been that good" or being a fad that just helped get us to where we are currently with console shooters and nothing more. Even if the stories usually amounted to popcorn flicks (sometimes bad ones like 3), there were a lot of great themes (2), great use of videogames as a storytelling medium (1 and 2), great level design (3), great art direction and armor/enemy designs (all the games but especially 3, ODST and Reach) and a great OST for all of the Bungie games (even 4 actually had some highlights there). And the way these games brought people together ... like I know that kind of tagline is a meme now but, damn. Forge :ok_hand:

Still one of the best songs in gaming history. 

That being said, Gears of War was also a big part of what made me the gamer :tm: I am today, 3 in particular stands in memory as one of the best games I've ever played. It was also awesome discovering Banjo & Kazooie back in the beginning of this console generation when I didn't have much to play on my 360. Though, I didn't really like much of what I played of Tooie. 

I'm excited to try out Fable when that gets released. 

Not playing racing sims, but taking it from colleague who's been deeply invested for years in iRacing, games like Forza and GT are considered simcades.