not-poignant:

The thing is, the ‘Solid Source’ is kind of a myth when it comes to folklore and fairytale, in that the vast majority of these tales were a) oral, and some of the best retellings we have are b) written and secondary or tertiary. We’ve already lost a lot of the best versions of the tales if the cultures are gone or Christianised or heavily damaged.

So it’s good to turf the ‘I need solid sources’ mindframe when researching this stuff? I mean, it’s – I believe – way better to read like 100 versions of say…the Ugly Duckling or Baba Yaga and Vasilisa the Brave, than it is to look for the ‘one true story.’ (Which doesn’t exist anyway, because in an oral tradition, they are meant to be changed and adapted to become relevant for whatever geographical group or class is hearing the story). Also fairytales and folklore are generally pretty short? You end up with huge huge variation.

However, I’ve written some stuff in the past that might be useful for you as well re: sources: 

Some book references.

Here’s another post with links / thoughts on the subject.

General thoughts and some info.

And there’s this aggregate post which is great:

Mythology aggregate. All the links!

It’s worth also looking into anthropological studies on different cultures that practice animism; fair warning though, they can be very problematic. (Especially earlier studies, which are often racist and/or xenophobic). 

Mostly with this stuff, it is actually often a matter of ‘quantity over quality’ which sounds weird but, there is so much and you can only really start by getting started and say…picking a favourite fairytale (or ‘species’ of fae) and researching them. You can hunt down more primary written sources (some of them are actually freely available on places like sacred-texts, due to copyright no longer holding on those sorts of texts) to distinguish between heavily Christianised tales and earlier versions; but you can also distinguish between those by researching animism tales/stories in different cultures etc.

Be prepared to give it a lot of your time, too. Like, I’m really only at the tip of the iceberg myself, and a lot of my studies have been going on since I was young and are very personal in that I research what has felt relevant to me over the years and I haven’t been doing this for say a course, or for a university or something (I’ve done some electives at university on this subject but ultimately, my research into these subjects is partly spiritually motivated, and partly about my fascination with ‘simple’ narratives told in complex or poignant ways to make them relevant).