Having listed several churches where a traveller would not feel out of place, I wanted to add, for balance and fairness, some “cults”, and in particular classic Anton LaVey type Satanists. One hour of browsing however yielded very little. One satanist site was last updated in 2005. Another one had coding messed up beyond hope. Given how much Satanists &Co are talked about in mass media, this failure to easily find any specifics was surprising.
The longest list of cults I was able to locate is www.ph4.ru/sect_sat.ph4#39. There you’ll find bits of info like names and places based on which you can continues the search if you need to but my strong impression is that diversity of religious life – as diversity in general – is lacking. There was a story about a group of Satanist teenagers who formed a satanist group on Yaroslavl and ate each other in 2008 but the story sounds somewhat madeup. That they could drink themselves to the point when slicing throats seems like a good idea is entirely credible but the link to Satanism makes it too coherent of a story to be believable.