Discovered Yakuza during Covid, and I don't think I could get more game per $ than I got with the series! For like $5 a game, I got at least 80 hours of play on each title and that's not even 100‰ completion.
For a casual gamer like myself, it's great buying them at a huge discount if what they're worth and they're full of so many side quests and mini games that I can just goof off as Kiryu for as long as I want.
The only thing I remember not liking is some of the poker and blackjack games are rigged/not random, which for all the things they put in these things seems trivial to have an actual working casino game.
The Virtua Fighter series never hooked me as a game, but the 3D graphics in the early arcade machines looked awesome at the time. It felt like a glimpse of the future.
Not produced by Sega but Shining Force and Shining Force II. And does anyone remember Vectorman? Tried to compete with DK Country with the pre-rendered 3D graphics.
OutRun series, especially OutRunners and OutRun 2.
Jet Set Radio Future.
Most people would consider it completely outclassed by competing Gran Turismo 3 and the later Forza Motorsport 1, but Sega GT 2002 is really nostalgic for me and I'd still love to actually beat it some day.
I'm not a beat em up fan but I'd call Streets of Rage 4 the best game in a genre I mostly don't like.
I also don't really like 3D fighters, but I greatly prefer Virtua Fighter and especially Fighting Vipers (and Sonic the Fighters but you said no Sonic) over Bandai Namco or Koei Tecmo's offerings.
NiGHTS into Dreams and Billy Hatcher will always hold a special place in my heart.
It's a bummer that Sega doesn't really do cartoony mascot-y games anymore outside of Sonic.
Like they have such a huge library of visually distinct characters just rotting away, only coming out every decade or so for a kart racing game or random cameo.
I guess not a Sega game but one that I loved on the Dreamcast that came to mind was Slave Zero so I looked it up to see if it was made by them, it's not, but it turns out there is a prequel due out in 9 days.
I'm so deep into Lost Judgement right now, I can't think of many Sega games other than it besides Ecco. LJ is the first Yakuza game I've played and I'm definitely gonna check out the rest after I'm done with it. Of the many things I enjoy, it also is very Sega-y, in how it feels like most of their arcade titles (like Crazy Taxi and such). But in a beat 'em/RPG/mystery novel fusion of a game.