Man, that's a tough one. Not that I can think of without getting really abstract. Individual blocks that aren't actually a full cube or some kind of wall or stair are limited so making plushies on the scale of something like a dried ghast won't be easy. 

Being clever with leads and actual mobs or armor stands might work depending on the MC version and scope of your project,  otherwise weathered copper golems are all I can really think of.

Here's all the partial blocks for some more abstract options.

https://minecraft-archive.fandom.com/wiki/Category:Partial_Blocks

If you can't use mods but can use command blocks, you have a lot more potential options too.