This is a long shot, but it would make certain spells much more interesting... In my Phantasmal Force I let the player choose from xvarts, bandits or bats to "summon." The "creatures" are, of course, created, not called from anywhere, so the caster can decide what to put on the stage. I had to dance around to make sure this really works differently from a basic summons, and I finally got it all to work. But now it occurs to me that it would be more exciting if the player had to learn about different creatures from experience, out in the world, instead of or perhaps in addition to the basic selection. After all, illusions need to be convincing, and how is one to know what an ogre looks like after growing up a shut-in in Candlekeep?
How could this learning be done? I think being around a creature of a type, let it be an ogre, for some minimum time, and close enough, within a short range, to study him, could set a Global, and with that Global it might be possible to change the available creatures menu. It's the first part that intrigues me. Any ideas about how that could be done? With a timer?