These three progressive levels of scale exercises (6 patterns each) will help practice fluency in all keys.
I’ve crafted a 30-minute warm-up/fundamentals routine to help me capitalize on small blocks of practice time that crop up in my teaching schedule.
Bill Adam’s Daily Routine, originally for trumpet, adapted for trombone
No sheet music is necessary for this buzzing routine. An example is given at the beginning of each aural exercise stimulus, and then the accompaniment continues while you buzz the pattern.