Mario, Zelda, Baldur's Gate.

Also, sex with hot girls.

Everything by Valve, unless you count the conspicuous absence of the number "3" anywhere as a strike(s) against their record.

I don't know why people are discounting spin-offs and OP never specified to omit them ...

There's at least 1 game that I can name in every game franchise aside from maybe some Valve owned IPs that will show a low point in a series ...

Out of curiosity I went and looked up all the console installmets of Super Mario and Zelda to see how many they made and what their average score was. First, I must explain the methodology. For the earlier games (essentially pre-N64) the scores are hard to come by. What I wound up doing was going through the available scores and averaging those specifically reviewing the Nes/Snes versions as opposed to some later Wii/GBA/VC version. I did this as many of the reviews are unfairly poor due to how recent they are, or they didn't like something about the port. Gamespot, for instance, gives the original Legend of Zelda a 72%, and he readily states that he's reviewing it with how the modern gamer would like it in mind as opposed to how good it was within the context of its own time.

The only two games I had real issues with were the original Super Mario and the original Zelda, both of which only listed 100%. As I read there WERE minor cricticisms (by crazy people), I've just counted both of them as 95% (the very early games are mere estimates due to a paucity of sources). Otherwise, by the time of the N64 there was a reliable metacritic for one or two of them, and from GC on that was the source I went with... I'd take the earlier games with a grain of salt as they typically trend towards a higher score than they likely would in a modern setting, though given most make "Best Games of All Time" lists they're not necessarily unfair.

Super Mario Bros Series (Console)

Super Mario Bros: 95%
Super Mario Bros 2: 90%
Super Mario Bros 3: 98.7% (this is when counting reviews specific to NES version, as later ports were not rated as highly)
Super Mario World: 99%
Super Mario World 2: 97%
Super Mario 64: 96.4%
Super Mario Sunshine: 92%
Super Mario Galaxy: 97%
New Super Mario Bros Wii: 87%
Super Mario Galaxy 2: 97%
New Super Mario Bros U: 84%
Super Mario 3D World: 93%
Super Mario Maker: 88%

Total: 13 Games
Highest Post-Snes Score (i.e. Reliable): Two at 97% (Both Galaxy games)
Lowest Score: 84%
Average Score: 93.4%

Main Zelda Series (Console)

The Legend of Zelda: 95%
The Adventure of Link: 82.8%
A Link to the Past: 92.3%
Ocarina of Time: 99%
Majora's Mask: 95%
The Wind Waker: 96%
Twilight Princess: 95.5%
Skyward Sword: 93%

Total: 8 games
Highest Post-Snes Score: 99 (Ocarina, highest all-time)
Lowest Score: 82.8%
Average Score: 93.7%

So yeah, I knew both were good but I'm honestly surprised by just how consistent they've been now that I've actually looked into it. Even accounting for the earlier Nes/Snes titles likely getting spotted a few points that more critical, modern reviewers likely would not grant them, the scores are still absurd.

That both could be averaging in the 90's after that many titles over the course of three decades and having never even strayed once into the 70's is one heck of an accomplishment.

Dark Souls 2 honestly was not that great, as for Bioshock that is easily Bioshock 2, which is easily the blacksheep. When I say the blacksheep that doesn't mean it is all bad, just that it doesn't match the overall quality of the franchise. 

As much as I hate GTAIV, I think I cannot say anything about GTA, so thats the only one that comes to mind. 

Never specified not to make the distinction either. Seems rather silly to consider Super Mario Bros and Mario Kart the same franchise, for instance, given how different they are.

Holy research, Batman!

Yeah, Super Mario and Zelda are, in my mind, the two greatest game series of all time for just that reason: sustained excellence for three decades.

Not flawless, but The Legend of Zelda and Rune Factory has been really good, making me come back to it

For me:

- Uncharted
- Super Mario (main platforming series, including both 2D and 3D titles)
- Batman Arkham

Souls
Metal Gear Solid
Bioshock
Arkham (The Rocksteady ones)