https://store.steampowered.com/app/3771220/HalfLife_Arena/

I'd just like to point out that Portal Stories: VR is erroneously labelled as being on Source, when it is actually on Unreal 4.

thank you greg for your work

https://store.steampowered.com/app/311810/Operation_Black_Mesa/?curator_clanid=6858478

https://store.steampowered.com/app/1908720/HalfLife_VR_Mod/?curator_clanid=4777282&utm_source=SteamDB

https://store.steampowered.com/app/2158860/JBMod/

https://store.steampowered.com/app/1828210/Requiem_Of_Science/

based and source pilled

Portal Reloaded (Source)
Aperture Salt mines (Source)
Hard life (Gold Src)
Operation Black Mesa (Source)
Aperture Desk job (Source 2)

Also Half life Overcharged, Half life 2 mmod, and Half life mmod might be on steam.

Operation Black Mesa and Hard life are both source games which haven't released but are source

Portal reloaded is a source game not listed

A mod for Portal 2 titled Portal Reloaded is in development

The Original Titanfall is now on steam

@Greg: Thanks.

Bear party adventure is a Source game that hasnt been listed

@RavenRonin: Only just seen this message. My bad, I've removed it from the list. :)

You guys accidentally labeled Estranged Act II as a Source Engine game, it's actually a Unreal Engine game. Good curator group non the less.