Flame

Flame is a rare ranged enchantment in Minecraft 1.21. Flame sets every arrow you fire alight, so each shot ignites its target and deals burning damage over time in addition to the arrow's normal impact.

There is only one level to it, so nothing needs upgrading — the instant it goes on your bow you have the whole effect (Arrows set targets on fire for 5 seconds (4 fire damage / 2 hearts)).

Flame exists at a single level only, so there is no scaling curve to climb — applying it to your bow hands you the complete effect in one step, with no Flame II to chase.

There is a single level. A Flame arrow that hits a mob burns it for about 5 seconds, dealing roughly 4 points of fire damage on top of the hit, and the flaming arrow can also light TNT, campfires and candles from a distance.

Flame fits exactly one item — the bow — and nothing else will accept it, so it is a dedicated bow enchantment through and through.

Flame has no exclusivity conflicts at all, so you can layer it onto a bow alongside every other enchantment that bow accepts without having to give anything up.

Flame can be rolled directly at an enchanting table, where reaching its top level of I on a bow generally wants a fully bookshelf-powered table at roughly level 10. When the enchanting table refuses to offer Flame, the same enchantment is available as a book from loot chest and villager trading for anvil application.

Its selection weight of 2 makes Flame a rare roll: it surfaces only now and then on a bow, so you may need to re-roll several times or simply trade a villager for the book.