Super Mario Bros, Zelda I, and A Link to the Past on too many platforms to remember.
Final Fantasy VI on SNES, PS1, and SNES Classic
Final Fantasy VII on PS1, Steam, PS4, and Switch.
Final Fantasy XII on PS2, PS4, and Switch, all physical versions.
Valkyria Chronicles on PS3, PS4, Steam, and Switch
Tokyo Mirage Sessions on Wii U and Switch
Secret of Mana on SNES, SNES Classic, and Switch
Super Metroid on SNES, Wii U, and Switch
Link’s Awakening on GB and Switch
Twilight Princess on GC and Wii U
Tales of Vesperia on 360 and Switch
Lunar: Silver Star Story on PS1, PSP, and iOS (one of very few mobile games I played.) and I’d gladly buy a Switch port.
FF Tactics on PS1 and PSP
Xenoblade Chronicles on Wii and Switch

Hitman: Blood Money on PS2, PS3 and PS4
Hitman: Absolution on PS3 and PS4
Soul Calibur 6 on PS4, digitally and physically

Every Zelda to recieve a rerelease, Chrono Trigger on SNES/DS/PS1/Mobile/PC, Chrono Cross PS1/PS3 (Digital), and quite a few others....to many to list them all.

Game Duplicates:

Assassin's Creed II (PS3, PS4 Digital)
Assassin's Creed II: Brotherhood (PS3, PS4 Digital)
Assassin's Creed II: Revelations (PS3, PS4 Digital)
Assassin's Creed III (PS3, PS4 Digital, Switch Physical)
Assassin's Creed: Liberation (PSVita, PS4 Digital, Switch Digital)
Assassin's Creed IV: Black Flag (PS3, PS4 Physical, PS4 Digital, Switch Physical)
Assassin's Creed Rogue (PS3, PS4 Digital, Switch Physical)
Assassin's Creed: Origins (PS4 Physical, PS4 Digital)
Assassin's Creed: Odyssey (PS4 Physical, PS4 Digital)
Assassin's Creed: Valhalla (PS4 Digital, PS5 Digital, PS5 Physical)
Batman: Arkham Asylum (PS3, PS4 Digital)
Batman: Arkham City (PS3, PS4 Digital)
Bloodborne (PS4 Physical Steelbook, PS4 Digital)
Borderlands (PC, PS3, PS4 Digital)
Borderlands: The Pre-sequel (PC, Xbone Physical, PS4 Digital)
Borderlands 2 (PC, PS3, Xbone Physical, PS4 Digital)
Borderlands 3 (PS4 Physical, PS4 Digital, PS5 Digital)
Dark Souls (PS3, PS4 Physical, PS4 Digital, Switch Physical)
Dark Souls II (PS4 Physical, PS4 Digital)
Dark Souls III (PS4 Physical, PS4 Digital)
Demon's Souls (PS3, PS5 Physical, PS5 Digital)
The Elder Scrolls V: Skyrim (PC, PC Special Edition, PS3, PS4 Physical, PS4 Digital)
Fallout 4 (PS4 Physical, PS4 Digital)
Final Fantasy (PS1, GBA, Android)
Final Fantasy II (PS1, GBA, Android)
Final Fantasy III (PSP, Android)
Final Fantasy IV (SNES, PS1, PSP, GBA, Android)
Final Fantasy V (PS1, Android)
Final Fantasy VI (SNES, PS1, PS3, Android)
Final Fantasy VII (PS1, PS3, PS4, PS4 Remake, Switch, PC)
Final Fantasy VIII (PS1, PS3, PS4, Switch, PC)
Final Fantasy IX (PS1, PS3, PS4, Switch, PC)
Final Fantasy X (PS2, PSVita, PS4 Physical, PS4 Digital, Switch Physical, Switch Digital)
Final Fantasy X-2 (PS2, PSVita, PS4 Digital, Switch Digital)
Final Fantasy XII (PS2 Steelbook, PS4 Physical, PS4 Digital, Switch Physical, Switch Digital)
Final Fantasy XV (PS4 Steelbook, PS4 Digital)
Final Fantasy Type-0 (PS4 Physical, PS4 Digital)
Final Fantasy Crystal Chronicles (GC, PS4 Digital)
Final Fantasy Tactics (PS1, PSP)
Ghost of Tsushima (PS4 Steelbook, PS4 Digital)
God of War (PS2, PS3)
God of War II (PS2, PS3)
God of War III (PS3, PS4 Digital)
God of War (PS4 Physical, PS4 Digital)
Grand Theft Auto V (PS3 Physical, PS4 Digital)
Gravity Rush (PSVita, PS4 Digital)
Horizon: Zero Dawn (PS4 Physical, PS4 Digital)
Jak and Daxter Collection (PSVita, PS4 Digital)
Kingdom Hearts (PS2, PS4 Digital)
Kingdom Hearts 2 (PS2, PS4 Digital)
Kingdom Hearts: Birth by Sleep (PSP, PS4 Digital)
Kingdom Hearts: Dream Drop Distance (3DS, PS4 Digital)
Mega Man Legacy Collection (PS4 Digital, Switch Digital, Switch Physical, PC)
- I also have Mega Man 1-4 on PS3's PS1 PSN options.
Mega Man Legacy Collection 2 (PS4 Digital, Switch Digital, PC)
Mega Man X Legacy Collection (PS4 Digital, Switch Digital, Switch Physical, PC)
- I also own every X title on their original playform. 1-3 on SNES, 4-6 on PS1, 7/8 on PS2.
- I also own 4-6 on PS3's PS1 PSN options
Mega Man X Legacy Collection 2 (PS4 Digital, Switch Digital)
Mega Man Zero/ZX Legacy Collection (PS4 Digital, Switch Digital, Switch Physical)
- I also own Mega Man Zero 1-4 on GBA and ZX on DS
Minecraft (PC, PS4 Physical, Switch Physical, Xbone Physical)
Ni No Kuni: Wrath of the White Witch (PS3 Physical, Ps4 Digital)
Ni No Kuni 2: Revenant Kingdom (PS4 Physical, PS4 Digital)
Nioh 1 (PS4 Physical, PS5 Digital)
Nioh 2 (PS4 Physical, PS4 Digital, PS5 Digital)
Ratchet & Clank 1-3 (PS2, PS3 Physical)
Rayman Legends (WiiU, Switch Physical, Switch Digital, Ps4 Physical, PS4 Digital)
Red Dead Redemption 2 (PS4 Physical, PS4 Digital)
Resident Evil 4 (GC, Wii, PS2, Switch Digital, Ps4 Digital)
Rock Band 4 (PS4 Physical, PS4 Digital)
Sega Genesis Collection (PS4 Digital, Switch Digital)
Sekiro: Shadows Die Twice (PS4 ultimate edition, PS4 Digital)
Sleeping Dogs (PS4 Digital, Xbone Physical)
Spider-Man (PS4 Physical, PS4 Digital, PS5 Digital)
Spider-Man Miles Morales (PS4 Digital, PS5 Physical, PS5 Digital)
Tearaway (PSVita, PS4)
Terraria (PC, PSVita, PS4 Physical, PS4 Digital, Switch Digital)
TitanFall 2 (PS4 Physical, PS4 Digital)
Uncharted: Drakes Fortune (PS3, PS4 Physical, PS4 Digital)
Uncharted 2: Among Thieves (PS3, PS4 Physical, PS4 Digital)
Uncharted 3: Drake's Deception (PS3, PS4 Physical, PS4 Digital)
The Witcher III: WIld Hunt (PS4 Physical, PS4 Digital, Switch Physical, Xbone Physical)
Yooka-Laylee (PS4 Physical, PS4 Digital)
Yooka-Laylee and the Impossible Lair (PS4 Physical, PS4 Digital, Switch Digital)

And that's just what I got off the top. Just games I have on PS4 in some capacity that I also have on other consoles (or other games in franchises that I remembered to add).

This isn't even including games I don't have Physically, like StarDew Valley which I have on PS4, Switch, and PC. Shovel Knight I have on PS4, Switch, and PC.

I might have a problem.

Hmm, I'll just name what I can remember off the top of my head

RDR2 (PC&Xbox one)
Nier Automata (PS4&PC)
Halo MCC (PC&Xbox One)
Resident Evil 2 (PC&Xbox One)
Stardew Valley (PC&Switch)
Overwatch (PC&Xbox One)
Resident Evil 4 (XB1&PC)
Minecraft (360, PC, PS4, Xbox One)

Edit:

Horizon Zero Dawn (PC & PS4)

I own a ton of the same games on various platforms but, one of the best in my opinion (other than OOT3ds and MM3D if that counts) gotta be MK8 on WiiU and Switch just a banging game. Everytime I play it I want a new Mario Kart to wow me like that one did

Do you have it on Steam? Just saying because it's now on sale...

I have it on Steam and on GoG. It's pretty much the original version of the game, which includes a different intro and different voice acting from the Spanish "FX" version. The Silicons' dubbing in spanish sound really more alien than the english version, for some reason.

I made a thread a long time ago called "games so nice you bought them twice" and I was pretty disgusted by how many times I've double, trippled, and even quadruple dipped. I think there are a few games I've bought five or more times on different hardware (if you include updated versions of games like Tomb Raider 2013 and Metal Gear Solid 3).

Right now, I don't even want to think about it--but I know there's a ton of games added to the list.

I know that feel, man. My list is pretty big, and that's a pretty basic list I did for like 20 minutes at 1 AM or something. Imagine how great I could be if I had it on other consoles.

I was thinking of making a chart. Name the game on the X axis, name the console on the Y, BAM