Unity editor tool
Shadow Baker
Static realtime shadows baked down to ground sprites
Real-time shadows cost a full extra pass over every caster. Nothing in a market square moves, so nothing there should be paying it.
Overview
Shadow Baker finds every static caster in a scene, renders its shadow from the sun into a sprite, drops that onto a ground decal, and switches the caster's real-time shadow casting off.
The atlas is what stops the decals becoming the new problem: packed, twenty replacements draw as one.