The Virtual Reality Media Alliance is 29 Facebook groups you can join that I help admin (someone asked for a list). In descending order of membership size.

1. Silicon Valley Global Network
https://www.facebook.com/groups/109971182359978/
84,151 Members

2. The Matrix of knowledge
https://www.facebook.com/groups/The.Matrix.of.Knowledge/
67,454

3. SteamVR
https://www.facebook.com/groups/htcvive/
17,890 Members

4. Gear VR, Oculus Rift, HTC Vive, Playstation VR, Daydream, Virtual Reality https://www.facebook.com/groups/gearvr/
17,758 Members

5. Oculus Rift Creative Community
https://www.facebook.com/groups/oculuscreative/
12,792 Members

6. Viveport and The Virtual Reality Media Alliance (VRMA) https://www.facebook.com/groups/vrmai/
9,935 Members

7. Neurophysics+
https://www.facebook.com/groups/IFLNeuro/
9,353 Members

8. Playstation VR https://www.facebook.com/groups/playstationvr/
6,398 Members

9. VR & AR — Software only https://www.facebook.com/groups/vrswonly/
4,062 Members

10. XR: MR, AR, VR + AI + Blockchain
https://www.facebook.com/groups/HololensAR/
3,828 Members

11. Theoretical and Computational Neuroscience
https://www.facebook.com/groups/theoretical.and.computational.neuroscience/
2,519 Members

12. Self-Aware Networks: Computational Biology, Neural Lace
https://www.facebook.com/groups/neomindcycle/
2,095 Members

13. San Francisco Virtual Reality SFVR
https://www.facebook.com/groups/sfvrtech/
2,044 Members

14. ARkit // Apple Augmented Reality Kit // WebAR // News & Dev https://www.facebook.com/groups/arvrweb/
869 Members Members

15. VRLA 2018
https://www.facebook.com/groups/1875581072656133/
363 Members

16. Volumetric Video VR AR Professionals: Point Cloud, 3D Mesh, Videogrammetry
https://www.facebook.com/groups/volumetric/
242 Members

17. Social Innovators: VR, AI, Blockchain
https://www.facebook.com/groups/socialvrai/
642

18. ARcore, Daydream, Tango, Mobile AR & VR
https://www.facebook.com/groups/daydreamvirtualreality/
292 Members

19. CES Fun Train
https://www.facebook.com/groups/cesvegas/
80 Members

20. ARcore // Android AR VR // Google // News // Developers // Artists
https://www.facebook.com/groups/arvrcore/
73 Members

21. AR VR Professionals — San Francisco, Bay Area & Silicon Valley Global
https://www.facebook.com/groups/ARVRPro/
73 Members

22. Death Star Robot
https://www.facebook.com/groups/deathstarrobot/
69 Members

23. LucidCam 3D 180 VR Point Clouds
https://www.facebook.com/groups/lucidcam/
69 Members

24. The Facebook Group Registry: Science, Technology, Engineering, Art, Math
https://www.facebook.com/groups/groupregister/
57 Members

Magic Leap
https://www.facebook.com/groups/magicleapglasses/
42 Members

25. Augmented Reality, Government Technology, Queer Friendly
https://www.facebook.com/groups/policedrones/
22 Members

26. Memes
https://www.facebook.com/groups/memespider/
21 Members

27. Blockchain Cryptocurrency ICO WhitePaper #StudyGroup
https://www.facebook.com/groups/blockchainwhitepaper/
12 Members

28. Soylent in VR
https://www.facebook.com/groups/soylentvr/
3 Members

29. VR AR AI Investor Stories & News
https://www.facebook.com/groups/1121216861311878/
2 Members