Enchant Exclusive:
An option to have parry only available when a shield is enchanted with Rebound.

Blacklist/Whitelist:
Modern versions have a tag to have certain projectiles be immune to parry. It be nice to have it for this as well but as a blacklist/whitelist instead since tags don't exist in 1.12.2.

Sound Indication:
Probably a sound to indicate whenever the projectile is successfully parried?