Could anyone give a tiny gist or guide to RImworld mod: Jecrell's Cults? :O I'd love to know if there's a manual in game that gives data or info about all the spells and 4 deities but yeah ._.;
Also nice seeing you on ludeon forums, CP 
Thanks

I'm less online than I would like because I just started a new job, and because I'm on my mobile data until I get internet at home next week (hopefully), and I need to save my GB for looking up data at work. But if you PM me in either forum I can try to answer to the extent of my knowledge. (Who are you in Ludeon, btw?)
The gods effects: brief summary
Cthulhu:
- Likely the best. Orbital insanity wave makes ships crash into the planet and deliver luxury goods. Can deliver some very nice and otherwise very expensive goodies. High success rate.
- Manifest Tentacle and Psionic Brain: Both are pretty decent, they will substitute a limb with a higher-functioning appendage. Can regenerate lost bodyparts&cure diseases in said bodypart. Psionic brain is actually targetteable and a good fix for brain damage
- Terrestial insanity wave: Never tried it, probably a good counter for massive sieges. I think it's better to make a sufficiently deadly killing ground, but it might work as an emergency button
Dagon: Not completely bad, but meh'ish. I think that as it stands now it's OK to build a little piety, but when it becomes impossible to build and keep piety with all the gods at once, I'd say his boons are the weakest of the lot. Sunken ship and lost treasure can deliver some sorely needed raw materials at times, and so they're not actually bad, but you're probably better off casting Orbital Insanity Wave and using whatever you dont need to buy whatever you actually want. Protect the Brood sucks: There's no guarantee that the summoned deep ones wont actually eat your pawns (or break through your base. Or eat friendlies...) while they're on their way to Dagon's circle. Didn't actually try tier 4.
Shub Niggurath: Pretty weak, IMO. To each his own. I'll admit I never tried most of the spells
- Fertility totem: There are better ways to grow crops, and it boosts production over a small area for a very short time.
- Black goats: ... I believe you have to hunt them afterwards, and have nasty stats. Haven't tried it because it doesn't seem very useful
- Forbidden knowledge: It can be useful if you have a big project and surplus sacrifice victims, but you can get this one from Nyarlathotep as well
I never got to use the higher tier spells because I felt the lower tier ones were underwhelming TBH
Hastur: This one I've tried little as well. I believe the most interesting thing he has is the summoning of Byakhees, which should actually be a very good transport system... but with a caveat: they are kind of buggy. They're supposed to be fixed now, but be wary of gamebreaking bugs and always save before using them. I never tried the unspeakable oath, but I figure it might be nice, too.
Nyarlathotep
- Starry wisdom will turn casters into psychopaths, and psychopath casters into cannibals. Can be casted more than once. It's not very useful, but arguably making citizens into psychopaths is a good move if you're sacrificing a lot, as to avoid debuffs (and cannibalism can mean having unlimited foodstuffs made from raiders, with a huge morale bonus)
- Forbidden knowledge: Like in Shub, but with better companion-spells.
- Chaos theory: This one is actually pretty good: You can use it to remove forbidden tasks from pawns, so you can use anyone for anything.
- Dark Emissary: Pretty overpowered, IMO. Sacrifice one prisoner, instantly get two cult-minded immigrants.