Severed Steel 3.0 seems to run without the client.

Deathtrap Dungeon === works perfect without Steam
Imperium Galactica === DOSBOX works without Steam

Tested on Win10 Pro.

DUSK can be added to that list. If you copy the DUSK folder and copy it to a PC without a Steam client it'll run. I've done it with the Linux version from Steam. NOTE: I do also own the gog release as well.

Starflight-style space and planet exploration roguelike Approaching Infinity:

https://store.steampowered.com/app/551620/Approaching_Infinity/

Conquest of Elysium 5 has a CD-Key, but you can enter it manually offline, outside of Steam:

https://store.steampowered.com/app/1606340/Conquest_of_Elysium_5/

Last Knight: Rogue Rider edition is also DRM-free:

https://store.steampowered.com/app/262210/Last_Knight_Rogue_Rider_Edition/

Dust: An Elysian Tail - The default Windows version requires Steam, however, the FNA-win32 build for Windows (accessible via the Beta channel) is DRM-free. Does not require steam_appid.txt and steam_api.dll files to run after the initial installation. Also moved the installation folder to another location and the game still worked. The FNA-win32 build also has a few advantages over the default Windows version, such as native support for DualShock 4 controllers (tested with V1 and V2 variants, functions are identical), and a few some compatibility (e.g. FMVs work properly on Windows 10 in Windowed mode due to being *.ogv files instead of *.wmv) over the default Windows build, however, it might be prone to crashes but the developer of this version has fixed some of the major ones recently.

Tested on Windows 10 Home 64-bit.

Steam version of Flynn Son of Crimson runs without the client. No special tricks required. Just click the .exe and enjoy.

Windows 7

Desperados III will not load at all without the steam client running. It locks up in the loading screen.Bit disappointing, considering the game is drm free on gog.

Tested on win 10 64 bit, renamed steam.exe, appid etc. No cigar.

Someone mentioned this a while ago, but I'd suggest also putting in the entries of the wiki either when the game was tested, when was its last depot update or what depot and manifests were tested.

Date of the test should be fairly simple, just getting the date of the comment or the date the user reports.

When was the last depot update should be really simple to get if who tested it has SteamDB's plugin. The date will appear immediately below the release date, like in this example where it says it was last updated in November 8, 2019.

For the last option, it'd be pretty tricky, as you'd need to dig the information on SteamDB (for example, starting here to find Starbound's depots and manifests), and the information isn't very clear.

Okay, we're all caught up again. As a reminder, all Steam games are assumed to require the Steam client unless reported on here; a game requiring the Steam client doesn't need to be reported here, unless someone specifically asked if anyone knew about that title in particular. Just trying to keep things easier to sift through.

I can put in the date that the game was tested (from the GOG post) if I remember, I think it's a good idea. I just don't have much time to jump on and update the wiki more than once a month or so.

All games verified today, March 27, 2022.

8 Eyes (app/1136080):
Includes a NES ROM. The ROM is the file "game" (no extension) in [Steam installation folder]/8 Eyes/res. Add .nes to the end of the file name for best compatibility with emulators. Windows binary not tested.

Brave Battle Saga - The Legend of The Magic Warrior (app/1028520):
Already in the list, but includes a Genesis/Mega Drive ROM. The ROM is the file "game" (no extension) in [Steam installation folder]/Brave Battle Saga - The Legend of The Magic Warrior/res. Add .bin to the end of the file name for best compatibility with emulators.

Dorke and Ymp (app/474810):
Already in the list, but includes a SNES ROM. The ROM is the file "game" (no extension) in [Steam installation folder]/Dorke and Ymp/res. Add .sfc to the end of the file name for best compatibility with emulators.

Dragonview (app/784010):
Already in the list, but includes a SNES ROM. The ROM is the file "game" (no extension) in [Steam installation folder]/Dragon View/res. Add .sfc to the end of the file name for best compatibility with emulators.

Gourmet Warriors (app/1104460):
Includes a SNES ROM. The ROM is the file "game" (no extension) in [Steam installation folder]/Gourmet Warriors/res. Add .sfc to the end of the file name for best compatibility with emulators. Windows binary not tested.

Impossamole (app/1137660):
Includes a TurboGrafx-16/PC Engine ROM. The ROM is the file "game" (no extension) in [Steam installation folder]/Impossamole/res. Add .pce to the end of the file name for best compatibility with emulators. Windows binary not tested.

Iron Commando (app/418640):
Already in the list, but includes a SNES ROM. The ROM is the file "game" (no extension) in [Steam installation folder]/Iron Commando/res. Add .sfc to the end of the file name for best compatibility with emulators.

All games verified today, March 27, 2022.

Legend (1994) (app/412380):
Already in the list, but includes a SNES ROM. The ROM is the file "game" (no extension) in [Steam installation folder]/Legend/res. Add .sfc to the end of the file name for best compatibility with emulators.

Nightshade (app/1028500):
Already in the list, but includes a NES ROM. The ROM is the file "game" (no extension) in [Steam installation folder]/Nightshade/res. Add .nes to the end of the file name for best compatibility with emulators.

Power Punch II (app/1137670):
Already in the list, but includes a NES ROM. The ROM is the file "game" (no extension) in [Steam installation folder]/Power Punch II/res. Add .nes to the end of the file name for best compatibility with emulators.

Radical Rex (app/1028490):
Already in the list, but includes a SNES ROM. The ROM is the file "game" (no extension) in [Steam installation folder]/Radical Rex/res. Add .sfc to the end of the file name for best compatibility with emulators.

Spiritual Warfare & Wisdom Tree Collection (app/624550):
Already in the list, but includes MS-DOS files. The files, at least in the Linux version, are all the files in the folder [Steam installation folder]/Spiritual Warfare & Wisdom Tree Collection/DOS/, including "BibleUnix.img". You may want to use the .conf files in [Steam installation folder]/Spiritual Warfare & Wisdom Tree Collection/Conf/.

Super 3-D Noah's Ark (app/371180):
Already in the list, but includes a MS-DOS version (also compatible with ECWolf) and a SNES ROM. All needed files are, at least in the Linux build, in [Steam installation folder]/Super 3-D Noah's Ark, with the SNES ROM being "Super Noah's Ark 3D (U).sfc", and the MS-DOS version being all other files except "libsteam_api.so" and "noah3d" (no extension). Can't check the Windows version, but iirc, the files are the same, but in separated folders.

Switchblade (app/1137650):
Includes a Genesis/Mega Drive ROM. The ROM is the file "game" (no extension) in [Steam installation folder]/Switchblade/res. Add .bin to the end of the file name for best compatibility with emulators. Windows binary not tested.

The Gadget Twins (app/1136090):
Includes a Genesis/Mega Drive ROM. The ROM is the file "game" (no extension) in [Steam installation folder]/The Gadget Twins/res. Add .bin to the end of the file name for best compatibility with emulators. Windows binary not tested.

Tinhead (app/1137690):
Includes a SNES ROM. The ROM is the file "game" (no extension) in [Steam installation folder]/Tinhead/res. Add .sfc to the end of the file name for best compatibility with emulators. Windows binary not tested.

Taimumari Definitive Edition.

It can be launched without the steam client.

PSA: To avoid the locking of this thread we should not link to the game store pages anymore.
Imo, it's better to find alternatives for reports. Is it possible to directly edit SteamWiki page somehow?

edit: Wow, the epic thread is already locked!
Thanks for all the participation guys!

@GOG: Fuck You for destroying this community! :P

Yes, this thread could well be locked tomorrow too as the Epic thread didn't even link directly to games in either the GOG forum thread or spreadsheet (whereas this thread's linked "SteamWiki" does) but still got locked for "advertising". So it might be best to come up with some off-site equivalent of this thread.

Signed! They are trying really hard this time to bring this down for good.