Avowed was very mid. I enjoyed it enough, but nothing about it was particularly brilliant or terrible.

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.

Mechwarrior online.

Free, online "shooter", good community, runs on linux, gameplay is dated and doesnt get tons of dev support anymore but its still how I kill an evening once or twice a week.

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

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

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.

Warhammer 40,000: Space Marine.

Greedfall

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.

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.

Well, when it comes to video games, despite being foundational, Mario Bros. At the time, it was mids, but there were a lot less truly great games, and less abysmal ones so it looked better than it was. The series got better, but that first one was kinda meh. It's all timing jumps, which is fine as far it as it goes, but there were both better and worse options on that console.

Away from video game, Life is about as meh as it gets. No real strategy, no depth. But it's a good time killer and you can play it with a table full of people drinking and not get bogged down or into arguments because of the game (unlike monopoly lol).