Minecraft wiki entry for Shield, associated text: Arrows from a crossbow enchanted with Piercing
This does not reduce the shield's durability.
Status effects from tipped arrows or shulker bullets ‌[BE only] [6]
Direct projectile damage is blocked, but the effect still carries through.
Status effects from splash/lingering potions, evokers' fangs, or breath from the ender dragon
Beam attacks from guardians or elder guardians
TNT that the blocking player lit themselves‌[JE only]
TNT that a redstone mechanism lit‌[JE only]
Teleport and fall damage
Strikes from a warden or any axe-wielding mob (e.g., vindicators, piglin brutes, zombies after disabling players shield they attack another time immediately)
Such strikes disable being able to use shields for 5 seconds‌[JE only]