Eclectic Satanism is just that — eclectic. It draws from diverse sources and combine ideas into a type of “personal religion.” Sometimes these ideas may be from various denominations of Satanism, or even from different religions such as Paganism, Wicca, Christianity, Agnosticism, etc. I have met Pagan Satanists, Christian Satanists, and even one girl who expressed interest in being a Jewish Satanist! All of these, provided they espouse the ideals of free-thought, independence, intelligence, and ambition, I view as valid pathways of Satanism. For an example, the Christian Satanist who claims that they must be “evil” and obey all of Satan’s orders without question in order to claim their place in Hell, I would not consider Satanic. But the Christian Satanist who has thought about the Bible and the nature of God and Satan and decided to worship Satan because he/she feels that that is the “right” thing to do for them, and have actually considered the ramifications of that, I would likely consider Satanic.
I should note that the majority of Satanists don’t agree with my view on this. It’s a common (although unfortunate, in my view) mindset of Satanists that only THEIR denomination is the correct one, and that at very least, you can’t be Satanic/Pagan or Satanic/Christian or anything like that. But as it’s my website, I’m including my views ;)
Since what one Eclectic Satanist believes will vary considerably from what another believes, one can’t really lay out the basic guidelines of what an Eclectic believes. About the only commonality is that the majority of their beliefs follow that of Satanism (as defined in the Foundations section). A person with a mix of Pagan and Satanic beliefs who most closely resembles Satanism, thus would be a Satanist. One who most closely resembles Paganism, would be a Pagan.
I know of no online organizations specifically devoted to forms of Eclectic Satanism. If you know any, let me know and I’ll post a link to them.