This might perhaps be more suited for a sub-mod, but the 19th and early 20th century saw the rise of various neo-pagan movements, and it would be cool to have this represented.

Perhaps if you have Romanticism and Nationalism (or Pan-Nationalism), and have enacted Freedom of Conscience or Total Separation, an event could pop up and convert some of your pops to an appropriate neo-pagan religion for the culture and region.

Converting a western country to neo-paganism would probably be unlikely, but maybe a decision might become available such as if you have a leader with an appropriate Ideology and religion, e.g. Ethno-Nationalist or Fascist to represent something like the Völkisch movement.

@Huyderman - This is certainly something I want to implement down the line, and I will definitely keep these ideas in mind for when I do.

At the moment, my main focus is the new Interest Groups I added in and making sure those run smoothly, so any new religions will take a bit.

Korean Shamanism (Mugyo), Vietnamese Folk Religion (Dao Luong), Druze, Ibadi Islam, Oriental Orthodox, and Atheism. Please let me know if you would like many more relatively large religions.

Maybe a joke Cthulhu religion? Have a option that is off for default.

hay could you add in Aleister Crowley's Thelema as a faith.
https://en.wikipedia.org/wiki/Thelema

Various pagan ? For example, the Druids or the Greek polytheists.
These can be found in ck3 as icons

Do you plan to add Ibadi Islam? The current branches of Islam in the game is only between Sunni and Shia, but Ibadi doesn't fall under either branches.

Hey. Can you add asatro(Åsatru) its Norse faith

Paganism doesn't really exist in the 19th century, but Germanic paganism with distinct Anglish, Nordic and German paganism would be nice, since in South Germanic paganism, the concept of Valhalla and Asir didn't exist as far I know like it did in Scandinavian paganism. Pganism power should be 0% or near it, with ways to boost it.

Bonuses from happy pagans could be like something war related, like lower war exhaustion for the pops that belong to it, rise in birthrate or a conscription bonus, with differences for the different Germanic pagan lobbies, like Anglish pagan bonuses could be higher assimilation for historic reasons.

Probably adding extra forms of Judaism like in ck3 or like reform and haredi