I play online a popular game at Plinko casino. I would like to create a community of like-minded people on social networks to share experiences and various secrets of the game. Maybe such groups already exist?

I think people would be interested in such a community. I try to join interest groups. If there are like-minded people sharing advice, telling different game features, then I think your group will quickly become popular. But you must conduct it regularly and actively. You can read about Plinko bord and social networks in this article https://www.plinko.bingo/articles/plinko50/index.html