1. Aeclectic Tarot
Forum has 3,651,134 posts.
https://www.tarotforum.net/  

2. GameTrailers
Forum has 14,078,088 posts.
http://forums.gametrailers.com/  

3. Games Dreams
Welcome to Games Dreams - Discussion forums for Facebook games, browsers games, MMO games, flash games, android games, iPhone iPad games, etc.
https://gamesdreams.com/  

4. Serebii.Net Forums
This is a discussion forum powered by vBulletin. To find out about vBulletin, go to http:www.vbulletin.com .
http://www.serebiiforums.com/forum.php  

5. Giant in the Playground Forums
The Giant in the Playground message boards, where fans of the Order of the Stick webcomic congregate to discuss gaming and such.
https://www.giantitp.com/forums/  

6. SYFY
Watch full episodes, get news, see trailers, videos and interviews for everything from the worlds of sci-fi, fantasy, horror and comics
http://forums.syfy.com/  

7. Build Your Own Arcade Controls
The NEW Build Your Own Arcade Controls - Index
http://forum.arcadecontrols.com/  

8. SlotForum
A forum community dedicated to slot car owners and enthusiasts. Come join the discussion about collections, racing, displays, models, track layouts, styles, reviews, accessories, classifieds, and...
https://www.slotforum.com/forums/