KKND Krossfire. Got it on PS1 and on GOG now.

Had a post about this a few days ago. I am currently going through my collection (large) and getting rid of duplicates and non games (discs with steam on them). Probably at around 500 now across platforms. I have 6 copies of baldurs gate, and lots where I have boxed or dvd copy and digital copy.

Several. Most notable the 3 Leisure Suit Larry Collections. The first as a tower of 5,25" disks (Just part 1-3; 5 was not a thing back then IIRC), the second on CD-Rom and finally some time ago digital (gog.com) when it was on a sale (I still have a 5,25" drive in the basement somewhere though).

Some gifted here, some bought there, but it stands to point: I own most of these on multiple platforms. Do note that if there's any game which I own both on Steam and GOG, then of course the Steam version is ignored. If not, well I'm probably not even playing it anymore.

-Duke Nukem 3D (GOG, Steam, Android) (this one is special because its the Megaton Edition on Steam, but using the awesome power of eduke32, I'm able to play the Megaton Edition expansions on the GOG version).
-Giana Sisters: Twisted Dreams (GOG, Steam)
-Sonic games (4 Episode II & I, CD, & SEGA All-Stars Racing) (Steam, Android)
-Terraria (Steam, Android)
-Need for Speed Most Wanted (Origin, Android)
-Beatbuddy: Tale of the Guardians (GOG, Android)
-VVVVVV (Humble Bundle PC & Android)
-Super Hexagon (Humble Bundle PC & Android)
-Thomas Was Alone (Humble Bundle PC & Android, Amazon Appstore)
-Ittle Dew (Humble Bundle PC & Android)
-Dead Space (Steam, Origin, Android)

Now for the kicker...
-Minecraft (Java for PC, Windows 10 Edition, PE on Amazon)

These two are special, because they are designed to get added to another platform automatically.
-Battlefield Bad Company 2 (Steam -> Origin)
-Alice Madness Returns (Steam -> Origin)


Well, that's all what I remember, for now.

yes my alice madness returns also got added to origin
im not sure but i think dragon age origins has the same function

origin at least seems to think its installed and then launches the steam version

I've bought:

Chrono Trigger on SNES and DS
Street Fighter 4 vanilla and arcade editions on PC (only to be screwed over by Ultra on steam, thanks Capcom)
Super Mario 64 on N64 and Wii
Star Fox 64 on N64 and Wii
Batman: Arkham Asylum and Arkham City on Xbox 360 and both vanilla and GOTY versions of each on PC.
Transformers: War for Cybertron on 360 and PC.

Games I own on PC (retail or non-steam) and console and re-bought on GOG:

Quake II
Jade Empire
Unreal Tournament
Unreal Tournament 2004
Beyond Good and Evil
Trine 2
GRiD
Dust: An Elysian Tail
Darksiders 2
Shantae: Risky's Revenge

I've also bought multiple copies of a few GOG games to give away or share with friends if that counts.

Never knew that was possible, but again, I haven't been a big fan of Steam by the time I got BFBC2. In fact, I only took advantage of buying BFBC2 on Steam because it was on sale, and then I took advantage of this very mechanic to just play it on Origin instead.

i am not sure if its a feature or origin got its wires crossed
maybe i should try installing dragon age on origin and see what happens

mmm, aside going from analog (CD's bought in the 90's) to digital (games rebought on GOG or another digital service) for convenience purposes, I don't really double-dip.

The only recent game which I have multiple versions is Terraria (first on Steam, then Android, then PS Vita then on GOG)

Since my last post I bought Android versions of a few more games I own: Baldur's Gate, BG2, Tomb Raider 2, Lego Batman 3, Syberia 2 and maybe some more.

Me and my brother bought Elder Scrolls: Oblivion two or three times because the DVD apparently was of really low quality. It just stopped working and the DVD drive stopped recognizing it but the DVD was required to play to the DRM forced us to buy the game again to continue playing it. I guess this is okay, because me and my brother were sharing the game and you know, that is piracy which is a capital offense and we just should be glad we had to buy multiple copies of the same game instead of being deported to North Korea and put into a gas chamber as the despicable being we are. Yay for DRM. DRM is justice. DRM is love.

The same happened with Gothic 3. We had to buy 2 DVDs and now I own a third copy of it on gog.

I think in my case the frontrunner remains the first part of the Gothic series. A friend of mine lent me the game which didn't require you to have the CD in the drive constantly. I liked it enough to buy the game soon after. Then I bought one copy for my brother. Then I picked up 4 copies for 5€ each because who knows, maybe you can give them away to friends. (Still have one of those left) And if I don't own it on gog it is just a matter of time until I will. I also own the Gothic Universe Box set. (Which means I also own a fourth copy of Gothic 3)

I also own several copies of Gothic II, one I bought on the day of release, then I bought the Add-On, somehow I lost the disk so I bought the gold version of Gothic II. Twice. Now I also own it on gog and in the gothic universe box.

Probably at least half of the classic games that end up GOG. I still have my disc copies of numerous games here (System Shock 2, KOTOR, Combat Mission, Doom, etc). Over the years I've probably owned over half a dozen versions of Doom, ranging from floppy, SEGA 32X, GBA, PSX, CD-ROM and gog download.

Sorry, the 'Extended "EE" Edition' gives you -15 copies, not +1.

Too many. Some on purpose, others accidentally.

Gifts
Psychonauts
Fight the Dragon
Neverwinter Nights

PS2 & PC
Bully/Canis Canem Edit

PC Retail & Digital
Planescape: Torment
Baldur's Gate 2
Neverwinter Nights 1 & 2
Fallout 1 & 2
Arcanum
Divine Divinity
Nox
Legacy of Kain: Soul Reaver
Gabriel Knight 3
etc.

I have to add though that I bought most of them at reduced price, even the retail versions, and I got rid of most of the latter eventually, once I had bought digital copies of the games in question.