What enchantments can bows have?

• Power - Extra damage (Up to Level 5)
• Punch - Knockback effect (Up to Level 2)
• Infinity - As long as there is one arrow in your inventory, you will have infinite arrows.
• Flame - Sets arrows and mobs on fire.
• Unbreaking - Extra Durability (Up to Level 3)
• Mending - Increases the item's durability as you gain XP (only costs XP to enchant initially)

Taken from the Minecraft Wiki.