• Battlefield 4 / 1 / V - just campaigns. What I remember from playthroughs were nice graphics and cool sound effects.
• Sniper Elite V2 Remastered - I have done it in few coop sessions with my brother. The ability to finish the full singleplayer campaign in coop is a great feature in games and this is what I look for nowadays.
• Hellblade: Senua Sacrifice - quite repetitive mechanic, but for story lovers is very fun to sink in
• Start Wars Battlefront II - similar opinion like for Battlefield series, singleplayer only for me
• Superliminal - fun game concept
• Layers of Fear 1&2/Blair Witch - I have rushed these games just for the sake of completion of my backlog titles.
• The Stanley Parable - comedy gold, frustrating at times, quite short, but highly recommended classic
• Aperture Desk Job - fun, interactive controller test game from Valve
• Serious Sam: Double D XXL - classic platformer from Serious Same universe with funny gun upgrades mechanic, with no political correctness

And some free short games/prologues:

• Outpath: First Journey - relaxing, but kinda simplistic Minecraft wannabe game
• Ale & Tale Tavern: First Pints - tavern manager game from first person view in medieval times
• The Riftbreaker: Prologue - solid prologue for strategy game with robots and aliens
• Helltaker - logic, rogue like game with nice humour
• The Looker - play The Witness first to get the reference, because this game is a parody
• Neon Beats - fun platformer, rhytm game
• Clap Clap - short, horror game
• Cats Hidden in Paris - find all cats on drawing type of game