Worms Good/Bad?

[Wanamaker]

I have an assortment of worms and wormlike creatures from my new live rock. Any thoughts on which are good vs bad?

Thank you!

 

[tuveyReefes]

bristle worms are good sand sifters and those are bristle worms

 

[Brandon3000]

Bristle worms are very common in this hobby. Pretty beneficial unless the population gets out of control.