Indestructible

Simple and lightweight, this mod adds an item that can give the Indestructible enchantment to every item that has durability and is enchantable.

As of 1.21, since the enchantment system changed, the system relies on the vanilla unbreakable component instead of an actual enchantment. Unsure if it will switch back to enchantments unless there are actual issues with that.

You just need three things, an anvil, an indestructible gem and blaze powder.

Place the gem on the anvil, then place the item to enchant and finally apply the enchantment by using a blaze powder on it. This method don't require an un-enchanted item and should keep the old enchantments.

 
Configs:

You can blacklist an item by adding it to the tag indestructible:blacklisted. From 0.6 onward, the catalyst is tag based and not hardcoded to blaze powder.

By default, items enchanted with the anvil-gem method will be fully repaired, it can be disabled in the configs.

From 0.2.2 to 0.6 (excluded) the enchantment can be applied on books (default: on) and its appearance in loot chests and villager trades can be enabled (default:off).

Note that items enchanted using the enchanted book won't have the fully-repair effect even if enabled. It will only trigger with the "old method". 

By default, the enchantment can be applied on books but obtaining it via loot chest or villager is disabled

Recipe for the gem:

https://discord.gg/99gghZMAW7

Simple and lightweight, this mod adds an item that can give the Indestructible enchantment to every item that has durability and is enchantable.

You just need three things, an anvil, an indestructible gem and blaze powder.

https://imgur.com/ET3bSG6

Place the gem on the anvil, then place the item to enchant and finally use a blaze powder on it to apply the enchantment. Indestructible can be applied to already enchanted items using this method (as opposed to the enchanting table).

Configs:

You can blacklist an item by adding it to the tag indestructible:blacklisted.

By default, items enchanted with the anvil-gem method will be fully repaired, it can be disabled in the configs.

The enchantment can be applied on books (default: on) and its appearance in loot chests and villager trades can be enabled (default:off).

Note that items enchanted using the enchanted book won't have the fully-repair effect even if enabled. It will only trigger with the "gem method".