I own 

Tekken 7 on PS4/Xbox One

Soul Calibur 6 on Xbox One/PS4

Dead or alive 6 on Xbox one/PS4

Dragon ball fighter z on Switch/PS4

Blaz Blue tag on PS4/Switch

Nights into dreams on Sega Saturn/Xbox One

Crazy taxi on Dreamcast/Xbox one etc

Ediit Link to the Past SNES/Gameboy

Not sure if it counts but I own physical and digital copies of Xenoblade 2, Octopath Traveler and Pikmin 3.

It counts multiple same versions

I have every Zelda game on everything it ever came out on, physically at least, an besides that not so much, except if you’re going to count remasters.

Remasters also count, I love zelda I had Link to the past SNES and Gameboy advance sp also past owner count .

I own Call of Duty Infinity Warfare twice on Xbox One.

I bought the CoD IW Legacy edition (with CoD4 Remastered) from Italian Amazon. I played CoD 4 Remastered first and CoD IW a few weeks later. After installing it I noticed that the game was indeed in Italian even though my Xbox was set to English. It turned out the game didn't have any English dub on the disc. Only languages available were Italian and Spanish.
This is VERY unusual for 8th gen games. I bought lots of games from Italy and France and they all came with at least English (aka the standard dub language) but Activision doesn't care and releases their CoD games without an English track in those countries.
Anyway I couldn't send it back anymore so I bought Infinite Warfare once more to be able to play it in English.

I own Final Fantasy X and X-2 on PS2, PS3, PS4, PSVita, PC, XBO and Switch. Don't think I've bought any other game on more than 2-3 platforms tops, lol.

Oh, I just realized. I have two copies of Pikmin 3 for Wii U, one unopened and the other used. 

ICO PS2 PAL version, PS2 US version, PS3 remaster
SotC, PS2 US version, PS3 remaster, PS4 remake
Ratchet and Clank series, PS2, PS3 remasters
Jak and Daxter series, PS2, PS3 remasters, PSP spin off.
Burnout 3 Takedown, PS2, XBox 360
Okami, PS2, PS4 remaster
Grim Fandango, physical PC edition, PS4 remaster
Zelda Windwaker, GC, WiiU remake
TLoU, PS3 version, PS4 remaster
Journey/Flower/Flow, digital PS3 and physical PS4 edition
GT Sport, steelbook physical edition, digital edition
No Man's sky, physical and digital edition.
DriveClub, physical edition and PSVR edition
Skyrim, PS3 and PSVR
Fez 360, PS4

Princess Mononoke wins though,
2 DVD editions, Hong Kong intl Blu-ray, Disney Blu-ray, Ghibli Steelbook edition

Minecraft comes close thanks to my kids, PC (x2), PS4, iPad and Dungeons on Switch

I own multiple copies of Submarine Titans on PC. They're the same edition, though.