Please help with this！Thanks！
Reading the word I thought it would mean something like ‘divining with everything’. But to be sure I googled it. There are a lot of pages about it, even a website with that name. I’m sure you already found that and read it before you posted here.
I have nothing to add beyond that sorry. I know how it feels when you ask an earnest question and it is ignored.
What they are trying to do is basically meta magick through psionic constructs. They are not as powerful as they make themselves out to be and extremely arrogant at least that is what personal experience dealing with some of them has shown me.
Learn psionics style magick and their methods of servitor creation but also study hermetics such as from Franz Bardon that will get you off to a good start. The rest is a bit of chaos magick and exploration. Bardon’s book on Evocation can give many spirits that can teach very powerful techniques which would fall into the category of what you want.
The Public Consumption, along with the forum, provides a solid basis of what Omnimancy is. Afterwards, all you have to do is figure out how to take it a step further, and usually, this can be accomplished through imagination, and spirit work. Although, both of these may be limited at times, so feel free to PM me for more information.