What's a serious esoterism site?

You need to give us a bit more direction. There are a lot of sites that are very deep into their subjects. Try looking at published research sites.

Search torrent sites etc. for this book ISBN-10: 0919345921 or ISBN-13: 978–0919345928.
The content is definitely thorough and reliable regarding British Tradition Wicca .

If you are into philosophy you may like this site Some of the articles are by subscription but there are a lot of good free ones.

@zenvelo List any you know, is what I humbly ask.
@Odysseus Thank you. I’m looking into it.
@LostInParadise Yes, I am into philosophy and I appreciate your suggestion. The site seems… varied.

Cheers, all.

There are some very deep interviews here on the topics of cosmology and philosophy.

Christian iconography or the interpretation of Christian symbolism in art is reasonably esoteric. I studied it and was fascinated and I am not Christian.

Various esoterica from philosopher stone to auras ro Gnostic texts to Tibetian singing bells

From “about us”—Dirk Gillabel has an extensive background in esoteric subjects.
In House of the Sun, a section of Soul Guidance, Dirk has written many articles about esoteric and spiritual subjects.

http://www.soul-guidance.com/houseofthesun/alchemy_3.htm
http://www.soul-guidance.com/
http://www.soul-guidance.com/houseofthesun/index.htm
From “about us”—Dirk Gillabel has an extensive background in esoteric subjects.
In House of the Sun, a section of Soul Guidance, Dirk has written many articles about esoteric and spiritual subjects.