Impecea: For Honor
As the game itself is already incorporated within Uplay, you won't be opening Steam but Uplay instead. Haha.....
Good point however, to make it more clear, we are looking for games that work independently of their client. This also brings up an interesting issue of although games might be free of the Steam client, depending on the game, they might have Uplay or Origin tied to them.
We do often list games from Epic as many of them, including the ones given away for free, are independent of their client after download. There are some exceptions of course. For Honor and Watch_Dogs, both given away on Epic, are tied to Ubisoft.
We should clear up, especially for anyone new, that games that are untethered from their client (in that they only use the client for downloading of the game itself and afterward the game can be played without the client) are the best options to list here.