It can be challenging to reward monks in D&D. Weapons, armor, or magical staves make up a large proportion of D&D 5e's magic items. More esoteric Wondrous Items are less useful in combat.
Weapons are some of the most prolific magic items in D&D 5e. The game has many swords, daggers, and more with spectacular additional effects. However, a plain +1 weapon is often all a character needs.