This app was mentioned in 21 comments, with an average of 3.33 upvotes
Even better, there is, of course, Oculus support. They also have "Caaaaarrrrrdbooooooarrd!" Which is the same game, but on phones dedicated to Cardboard style VR setups done with Android phones.
https://play.google.com/store/apps/details?id=com.dejobaangames.caaaaardboard
I highly suggest sitting in a spinny office chair to play it, or you will likely fall over or run into something.
https://play.google.com/store/apps/details?id=com.dejobaangames.caaaaardboard
This is my favourite. It's not free, but it's a great game. It's the one most of the people I show end up loving, and the most fun to watch people using.
Honestly beyond YouTube and Streetview, almost every app I've tried has been pretty disappointing. Try Caaaaardboard! it's the only game I played more than once.
The Default Daydream App, with the Daydream, IMO.
After that, I have forgotten the name (cause the name was something stupid like "aaaaaaaaaaaaaaaaaaaaaah") but it's a mobile phone port of the PC game with the same name.
Edit: remembered the name after a lot of googling, caaaaaaaaaaaardboard!!!!!
I recommend trying Caaaaardboard. It's the most intense VR game on the Play Store. You can only play it so much before you hurt either your neck or something else from bumping in to shit; but it's definitely worth spending some time. One of the few that is good quality too.
https://play.google.com/store/apps/details?id=com.dejobaangames.caaaaardboard&hl=en
I use it on PC with TrinusVR with Tridef 3D and play pc games with it. You can try CAAAAARDBOARD! (that's how it's called) which is an awesome game for Android where you fall
Caaaaardboard - really scary skydiving. Jump off of buildings. Move head to collect points and not get killed until safe place reached.
Costs 1,79€.
Theres already a version of the game that works on Google Cardboard, so the framework for simplistic tilt only controls is there. Whack in the SteamVR components to unity and push a new build and you'd be done basically.
https://play.google.com/store/apps/details?id=com.dejobaangames.caaaaardboard&hl=en
You should buy it from Google Play, but don't play it without a swivel chair! https://play.google.com/store/apps/details?id=com.dejobaangames.caaaaardboard&hl
Proton Pulse is another good Rift game in Google Play. https://play.google.com/store/apps/details?id=com.ZeroTransform.ProtonPulse&hl
Caaaaardboard 1,79€ Because it allows you to jump from the roof and skydive. Pretty cool experince. Most people like it.
Just wrote a long comment in response to another reply to my comment you can check out, but my favorite apps on it are probably Caaaaardboard! (a game that has you jump off skyscrapers and freefall), other games (in general) that let you fly around cities/areas, and I've had a lot of fun downloading concerts for people like Jack White and Elton John that put you in the audience and up on stage from different POVs as they're giving a concert.
It's honestly a different kind of experience than just watching a TV, so a screen size comparison doesn't make a lot of sense, but literally the 100-inch TV is going to have a higher resolution compared to any current VR headset, especially Google Cardboard (which is a lower end version aimed at making VR headsets affordable and available to everyone).
Here's a video of someone playing a horror game on the Oculus Rift (another VR headset, higher quality/price) that demonstrates the new dimension available: Mark puts on his headset and is now sitting in an entirely different house, with what could be a 100-inch TV in front of him, but instead of only being able to look at a fixed screen in front of him, the headset can simulate sounds and sights around him and he can look behind him, see the front door of his house open, see things pop out of the TV, etc etc.
The "mind blowing"-ness of it comes from it feeling uncannily real. The well-done games/apps make you feel like you're actually somewhere else, experiencing something instead of watching it.
Bonus: here's another video of a bunch of teens playing another horror game on a Rift.
My personal favorite game on the Cardboard is Caaaaardboard!, which has you jump off skyscrapers and try to hit targets as you're freefalling towards the ground -- and it's made a ton of my friends sick to their stomach.
TL;DR: if this is too long to read, don't even try to make money as a VR developer, because it will a very long and hard road.
I'll split it into four sections, continuing the numbering scheme, options already mentioned in italics. The order is just for consistency with the OP, not an indicator of importance.
Donations
Direct Sales
Services
Others
Remarks on sections/options, order the same as above:
In case you didn't guess: I've spend some time thinking about the subject. A mix of approaches will probably work best. There is a big hype surrounding VR/Cardboard, but not much of a market, the numbers are simply too low. So while an indie developer on Windows might actually have a tiny chance to just release a game and have it go viral, there are simply too few Cardboard users for mouth-to-mouth to work as a marketing strategy. A big part of the job for indies is networking. You probably won't have a huge marketing, so be prepared to interact heavily with your user community on all available channels, and learn to promote your product.
Also make sure you have a plan B, you have to be in it for the long run. Things will change over time, and I am extremely curious how well the Mattel VR View-Master will sell during the coming holiday season, which may send a lot of parents to the Play/App store looking for VR experiences to occupy their kids with their new toy. Parents pay a lot for toys.
Some previous threads (that I know of) about the opportunities for VR developers:
Caaaaardboard! by Dejobaan Games is fun. Worth the cost. Even though I haven't played it much after I bought it.
I basically agree, but there is one big problem: "The playing field is completely level" only because a lot of the existing developers don't develop for VR yet, as there is basically no market to sell to.
Example: AaaaaAAaaaAAAaaAAAAaAAAAA by Dejobaan Games, sold in several VR and no VR versions.
The interesting part is the Cardboard version. As a base jumping game with rounds that last about a minute and no input requirements besides head movement, this is almost the perfect game for Cardboard/casual VR. It was already known and is one of the few apps that is featured on the list of recommended apps by Google. There are very few good Cardboard apps, but as the Cardboard demo app passed the 1M downloads marker in early February, we know that there are a lot of Cardboards out there, so there should be a lot of potential buyers. But despite being pretty much the best game for Cardboard, having very few competitors, and being a third cheaper, it only sold a small fraction of the copies of the regular Android version, which (due to bundle sales etc.) would be dwarfed by the desktop version.
One of the reasons why the market place isn't already saturated by other indies with more experience is simply that they will wait until there is any money to be made. It still is a great time to start as a VR developer, but do not expect it to be easy. If you develop for VR exclusively, you will find it very hard to generate a lot of sales or to make a living. If you develop for other platforms too, you could distribute the development costs over a lot more sales, but will be playing against established developers.