Keep the setup simple on objects that appear many times on screen.
Use cheap effects first
Color changes, tint, hue shift, saturation, brightness, UV scroll, and simple dissolve are generally less complex than multi-sample effects; profile the final combination on your target device.
Limit expensive effects
Blur, bloom, soft shadow, glow, trails, heavy noise, and multi-sample outlines should be used on fewer objects.
Use the right variant
Do not use lit variants unless the sprite needs lights. Do not use GUI variants on SpriteRenderer objects.
Reduce unique materials
Presets reuse authored settings; they do not by themselves guarantee material sharing or fewer draw calls. UI Images use their own material instance for per-object control.