There's not nearly enough variety of large paintings or small ones for that matter.
As for Gargoyle blocks, make them from stone and redstone, mined with a pick. They place randomly like paintings do and can face blocks like coral flowers on the side or on top of a block.
This is a wishlist. You might want to split this into separate pages.
My suggestions: Enhancements - Throwable Fire Charges - On Phantoms and Elytra. Also check out The Minecraftian Language. This signature is not here to waste your space.