Well if we are going to talk about it, a sigil is a new age kind of thing, the lazy-man's rune, it has nothing to do with tulpas.
The 'servitor' is actually a humunculi, alchemists used creatures with these exact descriptions to aid them in their job, so, not tulpas.
The Egregore is just plain fucking wrong, a demon and an angel are different things from thoughforms, who the hell wrote this thing?
An egregore is basically a tulpa created by a bunch of people, like christianity's god for example.
And godform, thats just plain retarded mysticism 'nu yur tulpa is geting so strung its gonna become god'
When you create a tulpa you just allow a part of your brain to work separately, thats why only the creator of a tulpa can interact with it in any physical way.
That is also why some people go insane, this shit is a heavy toll on your brain.