Tough one, depends on what genres of games your into. For me I would grab the free ones first and then I recommend.
•bullets and More- small player base, even for a VR title, but it’s the jack of all trades multiplayer shooter, and the battle Royal on the new map is brilliant too. My favourite VR online FPS, and has the best guns and weapon attachments too.
•pavlov- another FPS, bigger player base than Pavlov, but much faster gameplay, with an active modding community with a good selection of user made maps.
•Onward- Last VR multiplayer FPS title, and the darling on the VR FPS community, the game is highly regarded and you will read the term ‘Onward locomotion’ on various reddit posts about upcoming games. It has the largest community of any VR FPS title, and has a great community, people refer to it VR Arma due to its realism, but in truth It plays more like R6 Siege with its 1 life per round gameplay.
•SuperHot VR- it’s short, and not worth the full price because of how short it is, but my god, does it make you feel like a badass, more so than any VR title I have played to date
•Dirt Rally- the best VR racing game in VR
•Elite Dangerous- still yet too play it, but for £4.99 it’s worth the punt
•Fallout4 VR- expensive and will take up the majority of your credit, but it’s fallout, in VR.
I have a Rift and as such most of my titles are tied to Oculus Home, but any VR owner owes it to themselves to take a look at Echo Arena, it’s free on Oculus Home, use a free tool called Revive to use Oculus Home with a HTC Vive.
*Little rant inbound* Hopefully one day Oculus opens its doors an natively supports other headsets, VR needs to be open, it’s a peripheral, not a platform.