Hitman games

Intravenous 2, although the objectives are more "rescue this guy/kill this guy/find incriminating evidence/etc"

Similar "hide in the dark" mechanics though and a Splinter Cell style light and sound meter

Styx. The levels are huge and there are plenty of different routes you can take,use your abilities to distract enemies and so on. The game however rewards you more by avoiding any killing,and you cant dispatch enemies without killing them

imo Deus Ex games, Metal Gear Solid V is pretty open, and Hitman games. These games have levels that can be replayed in different ways.

The Thief series, to a degree as well as Dishonored to a lesser extent.

If you don't mind a bit of spooks and an older game then The Dark Mod might be something you'd enjoy. It's completely free (not on Steam) and you can easily download fan made levels. It's a game made by fans of the Thief series.

Originally posted by Echoist:

If you don't mind a bit of spooks and an older game then The Dark Mod might be something you'd enjoy. It's completely free (not on Steam) and you can easily download fan made levels. It's a game made by fans of the Thief series.

I don't know how to install Thief fan missions.

Do not try Intravenous 2, unless you dislike proper stealth and prefer go John Wick.

metro 2033 and metro Last light