You seem to be using the actual textures from Thaumcraft.
(https://minecraft.curseforge.com/projects/thaumcraft)

I sent a message to Azanor with a link to this mod/thread, you should sort it out with him.

So, if we're talking about the Essentia icons, I believe they're free assets from https://game-icons.net/

I haven't actually played this mod yet and there could be other reused assets, but as far as the icons, I think they're fair game.

I have already attempted to contact him. If he ever replies that he wants me to use different assets i will be willing to comply.