Add the ability to display entities (Armor stand, cart, etc.) in the material list of a loaded schematic. I would love to see the passive and hostile mob icons in a cart as well, so they look nicer in the block list :)

Items for entities are planned for the material list. But stuff like rendering a mob in a minecart is not feasible, as there is no context for that in the material list.

The mod converts all the blocks from the schematic into ItemStacks for the material list, and there is no concept for mob in a cart when dealing with items (unless it's a NBT-picked version of an item maybe?). And also rendering an entity of any kind would mean having to use the entity renderer for that entity, which means that there would need to be an entity to render, and that entity would need to be in some kind of fake world. The material list does not currently use or need a fake world. And I won't add all that complexity to that system just for a tiny detail like rendering a mob in a cart. It would also not work sanely with the item collection and counting logic, as you can't collect an item for a mob in a cart in survival. Instead the minecart item, and then separately probably the spawn egg for the mob in the cart will be on the list. Obviously you can't get the spawn eggs in survival either, but at least it would show you the number of each mob type.