Nintendo did too many things to count them. They basically saved the whole industry after the massive crash in the 80s, they kept innovating controllers and every controller from today has something from Nintendo in it. They also set the tone in terms of software and created some of the most beloved and frankly best video game franchises in history. And Nintendo is the driving force when it comes to gaming on the go, apart from smartphone games which I won't count because they suck like 99.9 % of the time. =P

Sony brought gaming to the masses. NES and SNES sold good, sure. But Sony took it to the next level and their competition lead to countless technical breckthroughs. In the PS3 era, Sony delivered some truly amazing first party games, many of which created franchises still relevant to this very day.

Microsoft... I'm sure they did something too. Some folks said online stuff. Yeah, the sure as hell brought paid subscription services to us. Thanks for that. Then there's Kinect and TV. Maybe Gamepass? Some folks seem to like that. They brought the first console ever with basically zero exclusives! I guess that's something. But sorry, mostly Microsoft has just been a copycat. I guess their endless piles of cash at least kept Sony in check in the last 20 years.

Nintendo: Saving console gaming (computer gaming was fine and thriving throughout the videogame crash of 1983) with the NES and Super Mario Bros.

Sony: Making videogames more for teens and tweens instead just to kids, nerds or families, thus bringing it to the mainstream.

Microsoft: On console, bringing online features to the mainstream. On PC, standardizing 3D graphics through DirectX (before, each manufacturer had his own standards, so early PC 3D games worked only with specific 3D GPUs)

Nintendo was the OG major console house and managed to keep the scene alive through some tough times.
Microsoft was the online pioneer and also has kept Sony on their toes so as to not get too complacent.
Sony showed that it was possible to make it in the console business as a newcomer. They truly opened up that very exclusive game and Microsoft followed as well. There were also others that did not make it very long, it is not an easy breakthrough to make.
They also made console gaming attractive to people like me, who didn't care for Nintendo games but weren't PC gamers either.

Nintendo: NES saving console gaming and ushering "Japan", portable gaming, D-pad, software innovation, several inspirational titles.

Sony: Dual Analog (the controller), Playstation 1 and 2 making gaming cool-ish, Gran Turismo, ICO, Souls.

Microsoft: Mainstreaming console online gaming (though I do wish it was free). Keeping Sony in check.

Nintendo: for the GamePad over the Janky Joysticks of the past. Motion controls like Rumble Packs, HD Rumble and Populizing the Analog stick and 3D gaming and Portable gaming (GameBoy/Switch)

Sony: Populizing Twin Analog Sticks and 4 Shoulder buttons plus made Licensed Racing Games a thing, Share button.

Xbox: Built in Harddrive, Standardised Online Gaming, Achievement System, Digital gaming (Consoles) Xbox Live, and Populized Analoged Placement, Home Button.

Nintendo is easy, interactivity. As forerunners of the entire thing, their games have stood the test of time but it was up to devs back then to make things work, over time, what Nintendo did better than anyone is come up with unique ways to play, from the power glove to the Switch 2's mouse. Each gen they have tried and added stuff to make playing games easy and fun. Powerglove. :P Gameboy was small, easy to pickup and play and batteries lasted 17years. N64 and GC had 4 player ports by default, GC was small and easily carried, Wii had motion so good everyone else tried to copy it. 3DS was the only 3D we ever had that worked (shame this didn't take off, still never experienced it, not counting VR). Wii U and it's 'switching'... the switch and it's ability to .... switch. :P

Sony, this is an easy one, sure people are saying dual sticks but i think that would have happened regardless but technology. Specially being a technology company they seem to want to push the technology in each console, CDs on PS1 not only helped devs fit games but it massively lowered costs. DVD allowed the same but also massively helped the movie industry for sure. PS3 had blu-ray and bluetooth and wireless. PS4 had recording and steaming tech and the PS5 has the dualsense, honestly an impressive bit of tech considering it's only £60. 

Microsoft, now sadly this is harder. I guess if I'm going to say positive, it's online gaming. I think their push for it on Xbox helped push it forward as I'm not sure Sony or Nintendo would have had such a push if not, comes with a hit though, we now pay for our online gaming.

Nintendo.

There can't be just one. From their revolutionary software, which gave gaming the huge boost it needed in the 1980s, to standardizing the Dpad. While Vectrex had analog in 1982, N64 popularized it. Nintendo has made countless innovations in both software and hardware. They standardized shoulder buttons—not the first, as XE 1AP Controller for SEGA Mega Drive was the first that I know of. Nintendo's handhelds redefined portable gaming. From ecominics. To the target audience. You think DS was the first to target casuals for Nintendo? A Game Boy came with Tetris for that reason, and commercials targeting businessmen in 1989.

Sony.

They took SEGA's playbook of targeting older gamers in marketing and elevated it to a further level. The dual analog, while not the first, as again that is the XE 1AP for SEGA Mega Drive. Helped standardize dual analog. The concept of a game console also being an all-in-one entertainment center goes back to the 90s. Pioneer Laseractive. 3D0. CDi and more. Sony finally brought it mainstream with PS2.

Xbox.

While SEGA pushed for online for years and DLC existed on consoles before even on N64 and Dreamcast. Downloadable games on DC. SEGANET while forward thinking. Xbox Live is one that really figured it out. SEGA intended to put a HDD in the Dreamcast along with a DVD drive, but was short on cash. So Xbox beat them to it. Xbox with 360 also helped kickstart the indie game revolution on 360.

Nintendo - Their IP
Sony - Making gaming more mainstream, Optical Media
Xbox - Xbox Live

Nintendo never did "save" gaming, it was doing fine and growing in Japan and Europe all along, even home consoles (unless you happened to be an Atari owner). That's just an example of US-centrism that somehow seeped into public consciousness.

It's very unrealistic to believe the US would forego gaming entirely forever and ever if the NES didn't release there. Eventually the market would recover on its own, even if it's a more PC-centric one.

I consider good handheld gaming Nintendo's best contribution. That includes both hardware and software that works well in the medium.

Sony made gaming cooler, making it less of an instant ick for the people not yet baptized in the culmination of digital entertainment.

Microsoft. Well... They... They added that Pinball game to windows.