If you don't have them already, the Thief series. The games are about, who could have guessed, a thief you play. It plays in a medieval fantasy world with slight steampunk influence.
Every level is a job you get, stealing a specific item.
The games come with handdrawn maps of the building you plan to rob, which I like more than the computer generated maps you see in every other game.
You can use different arrows to achieve your goals. Fire arrows light enemies and other stuff, water arrows extinguish torches and remove blood stains on floors, moss arrows mute your movements, rope arrows give you access to new routes. There are some more but it's more interesting to find them on your own.
The game heavily emphasize that you should take the silent route and never harm anyone (on the highest difficulty you are even not allowed to harm anyone or you immediatly fail your contract). While you have (at least in the first game) a sword, it won't help you much because a single enemy can already kill you easily. You are a thief after all and not an assassin. As far as I remeber drawing the sword makes also a lot of sound and the blade reflects light sources, making you better visible in dark corners. It is always better to just knock them out and hide their bodies away. It won't leave a blood stain that way that you have to remove (saving water arrows).
The games got a lot of praise because of their unique gameplay. They are really very fun to play and I can always suggest them. Except the last one (Thief from Square Enix).
While I really like the other purchased franchises of SE (Tomb Raider, Hitman, Deus Ex), I don't like Thief from them. It isn't a bad game but it is very bad optimised, making even a very good PC cry. This is a common problem and despite the existence of several fan made fixes for the fps drops and stuttering graphics, SE themself fail to admit that they messed this one up and never showed up with a patch (and never will, the game is too old for that). even my pc had problems with it and I had TR turned on its highest graphic settings with no problems.
It's just a mess and taints the entire game. Plus, you have one of the most annoying starts and sidekicks I've ever seen in any video game. The whole prologue is so annoying, I wanted to stop. It gets better afterwards (because your sidekick disappears) but thereare still a lot of flaws. For example there are absolute no uses for your arrows.
I got dozens of water arrows but almost every light source in this game is electrical and you have to find a switch, walk to it and press it to turn it off. And the few non-electric light sources are always next to a guard who lights it up at he moment you put it out.