Scholarly Resources
A bunch of information about Irish paganism based on actual scholarly research. They also have a YouTube channel. Highly recommend.
Indexes/References
Museum of Witchcraft and Magic
Not really sure how viable all of the stuff this place says is, but its collection does have some interesting stuff in it.
Huge collection of old Irish documents, with tons of references to Irish folklore and traditions.
Big, big index of different websites related to all sorts of religions and spiritual beliefs.
YouTubers/Podcasts
Not the most formal of resources, but you can't deny the vibes that radiate from her entire channel. Recommend for some more lighthearted witchy content or a perspective on working with the good folk.
Honestly a bit more clickbaity in terms of resources for Irish paganism. But everything seems to be well-researched and based in actual Irish culture, so it's not a bad starting point.