Free online tuner: Tuner
Free online metronome: Metronome
Practice your fingerings or note names here: Music Racer
Learn music theory: Music Theory.net
Print staff paper: Staff Paper
Work on your sight reading: Practice Sight Reading.com
Breathing Gym: Breathing Gym
Optimize your music practice: 10 Ways
Play-Along tracks and lead sheets for most jazz standards: Learn Jazz Standards
Practice Articles 2013