yeah, be careful with church groups and such.. some can be nice & helpful, some can be a bit 'cult-like' or like sects, and can try to 'suck you in' or brainwash you, and may want to determine who you can or cannot marry etc.
be careful with Jehovah's witnesses or such, they can be very determined. I think I heard about them determining who you can marry too etc.
some sects or such may also want you to volunteer a lot of your time, like become a 'missionary' for them to 'spread the word' (someone I know said a sect/group wanted her to practically stop studying and work full-time for them without pay), or may want you to part with your money.. yup, do research..
Personally, I'm more spiritual than religious, and quite open-minded.. some of this is not really tolerated by some of these groups, they want people to suspend intelligence and critical thinking in favor of 'one and true belief'...
If you were raised Christian/catholic or in another belief, there may be sub-groups within that that you can join, check what is available locally... research options within your current belief system first.. and options of clubs or associations or meet-ups that are non-religious.. (poetry clubs/literary clubs, eco clubs, anything based on your interests etc)