I'll be honest and admit I used to despise the Assassin's Creed series. I had played the first one back in 2011 or 2012 and found it to be extremely repetitive and frustrating, which made it hard for me to understand why it was so praised and how anyone could want yearly sequels for that.
Fast-forward to 2019: The Ezio Collection goes on sale and I buy it because the price is really nice and I'm thinking maybe I should give the series a second chance. And then it clicks. Kinda. I never warmed up to Ezio, but he did become a more interesting character as his story moved forward, and the gameplay ended up being quite addictive with its cycle of completing the activities of an area and advancing through the main plot to unlock more areas with more stuff to do. I ended up playing the whole series, from the first to Odyssey, and now I sort of love it as a comfort food type of game.
Far Cry is another series that I like a lot, but I only care for the main titles and don't care much for the spin-offs.
I enjoy GTA and RDR. Their worlds are big and detailed in ways that make me glad just to be able to roam around and do dumb stuff. That said, I wish Rockstar would both trim the fat from the stories they want to tell, making them more focused, and improving on their mission design so these parts would be more flexible. I also think they really dropped the ball with GTA5's characters and plot.
Call of Duty is a series whose games I enjoy but would never pay full price for. Their campaigns are fun, some of them are really great, but if there is a series that I wouldn't care at all if it simply disappeared, this is the one. Never tried its multiplayer, never will.
Destiny is like a drug to me. I played it for a total of about 2400 hours in a year and a half, and decided to quit it cold turkey when I realized how damaging it was being to my social life. When Destiny 2 came out, I played it for two days before deleting it. All the addictive elements were there, and I didn't want to risk going down that rabbit hole again. I'll give it another shot when my Series X arrives, but I'll try to play it more casually and keep away from PvP and co-op activities.
Fortnite never had any appeal to me.
Arkane, id software, Machine Games, Tango Gameworks (does it count as Western?), and, to a lesser degree, Bethesda, are all devs whose output I love.