Godus.

I know lots of people hate it but taken in isolation it's okay. I found its aesthetics charming and its pace generally pretty chill. It wasn't good but it wasn't terrible. Low medium perhaps but I have comfortable memories of listening to an audiobook whilst playing it.

Just Cause 3

Movement was more annoying than Just Cause 2

Assault Spy comes to mind.

And Mad Max maybe?

we are in a golden age of medium good action games. lies of p, stellar blade, khazan the first berserker, another crab's treasure come to mind for me.

non-fromsoft soulslikes are starting to find their voice. they're not quite great yet, but they're competent now.

Sackboy a Big Adventure. Absolutely no ill will towards it, and the issue may lie more with me than the game, but it just felt very "okay" for me.

Minesweeper

Rogue Trooper

I suppose Resident Evil 8? The scares weren't very scary, the exploration was all very fake, and the bosses all showed up for attendance. It definitely functioned, but it didn't impress in the way previous entries did. It wasn't frustratingly bad like 5, nor was it interestingly bad like 6. It just felt like a lesser version of what they've given me before, somewhere between 4 and 7.

The incredible adventures of Van Helsing. Decent rpg with loot but was fairly imbalanced among character classes. The real winner was the mini tower defense games in it and the spinoff tower defense game, imo.

Team Fortress 2:

I'd say its gameplay is more "robust" than special. Like you can have any and every kind of fight in TF2 but none of it is more special than an FPS that specializes in any game mode.

Every Halloween, I play this Xbox 360 (I think it's also on PC now) game called Bullet Witch.

Basically a third-person shooter with postapocalyptic supernatural horror theme. You play as a witch who shoots zombies and weird creatures with a magic machine gun broom thing. Also you get spells. Some are bloody awesome.

This game is peak Xbox 360 to the core. The distinct memorable thing about it is that I can actually list good and bad things about it. Level design varies between meh and decent. Some of the particular setpieces are pretty awesome though. (You get to fight at an airport, and you get to do a boss fight at the top of the plane mid-flight!) Spells are fun. The mega-spells are hella fun. (Just call up lightning and watch stuff explode.) Shooting is kinda jank but it works. Jank is explained by lore. (Why is friendly fire not a thing? Well, you see, this is a magic machine gun broom thing, so bullets dodge the civilians and allies by ~*~magic~*~.) Enemy designs are nothing to write home about at first glance, but are actually kinda memorable. (You first meet up the zombies and hey, they're talking zombies. With military helmets and guns. Like, what? You don't see this every day.) There are some things that seem just not very well designed, like there's these gigantic enemies that serve as minibosses and they're a lot less scary when you note the AI is probably bugged and they often just decide to stand at place for a while and eat a lot of bullets.

I got this thing in the bargain bin. It's a zombie shooty game that's perfect for Halloween so that's what I use it for. That's all it does. That's all I could ask it for. And it's fine at it.

From the 360 Era — Too Human
The control scheme is bizarre at first (right stick is melee) but it works once you're used to it. It's Sci-Fi Norse mythology, I recall it having a pretty solid art style. I picked it up used from either Blockbuster or EB because I wanted to see just how bad it was, ended up enjoying it far more than I expected, I'll give it a "Yeah, it's ok", disc images are readily available if you want to emulate it, can find a physical copy cheap online too if that's your thing.

This is the game that ended up taking down its studio (Silicon Knights, they developed Eternal Darkness: Sanity's Requiem and Blood Omen: Legacy of Kain, they tried to sue Epic, who countersued and won, probably added to my initial interested tbh.

Pretty much every korean MMORPG released from 2006-2014, as they were desperately trying to be "World of Warcraft, but better". Perfect World, Aion, ArcheAge, 4story, Granado Espada, etc etc etc, even when you have the better experience of playing on a private server with significantly less P2W (as in, nearly everyone gets most of the shop for free)

To me, personally, ArcheAge would be the best fit for "dead medium quality". It boasts naval combat, which is meh; player run trade caravans, which probably only worked as intended in the first 2 months after launch; limits on gathering and crafting, which just forces free players to buy premium; graphics are the generic korean mmo variety, pretty but almost impossible to distinguish between games; music, enemies, dungeons and most gear exist

Shadwen.

Warhammer 40,000: Space Marine.

Elex 1 and Elex 2

The term you're looking for is "Extra Medium".