The vast amount of mallet choices can be overwhelming for band directors and students. A simple way to start a mallet collection is to have the minimum pairs of mallets that will sound good on all of the percussion instruments.
Here is an example starter collection:
1 pair of concert drumsticks
1 pair of medium or hard yarn marimba mallets (can be use for marimba, vibraphone, suspended cymbal etc..)
1 pair of hard plastic mallets for xylophone or bells
1 pair of medium rubber mallets for marimba, xylophone, woodblocks, etc…
1 pair of medium timpani mallets (for timpani only - not for cymbals)
From there you add more and more mallets to achieve a wide variety of sound choices.