The latest Humble Bundle, at its highest tier, collects eight VR games including The Walking Dead: Saints & Sinners, which our reviewer Rick Lane called "easily my favourite VR game since SUPERHOT". If you want a VR game with a campaign you'll be playing for more than 10 hours, and you already have Half-Life: Alyx, this is what you're looking for.
You'd pay $40 for that game alone right now on Steam, but it's in the Humble Fall VR Bundle for $17. That also nets you a couple of our other favorite games you need an expensive headset to play—I Expect You to Die (which dumps you in a series of spy thriller situations like having to defuse a bomb or escape a submarine), and Creed: Rise to Glory (a boxing game that doubles as a workout, if you've got the space for it).
Also included are Killing Floor Incursion, Raw Data, A-Tech Cybernetic, Archangel: Hellfire, and an Early Access military FPS called Zero Caliber. If you recently acquired a VR headset then all you need to do is buy this then go pick up Beat Saber and you've got a solid library of games to be getting on with.
Here's our list of the best VR games on PC.