I've been trying to develop my own style of imagery suitable for the Familiar game. I've got a few default styles, some of which are more "anime" inspired, some use more photographic referencing, others are just freehand following of concepts as they unfold in my head. I'm still trying to work out what's going to work best for this game, and while these images are in the general ball park, I'm not sure they're exactly what I'm after.
The first image is an example of a typical mage and familiar, perhaps meeting one another for the first time and only just starting their metaphysical journey together.
This is more like a page from a grimoire, bestiary, or other tome of mystic knowledge. Perhaps describing the true forms of the familiars as they exist in the spirit realms, perhaps describing metaphysical threats that bring horror or chaos to the mundane world.