Online Tone Generator - We tune to a drone on concert F everyday and this is a great thing to practice with. Click on F4 to tune to what we tune to everyday or pick random notes that are the tonic of what you are working on to continue to refine your intonation skills. This is just a tone generator so it won't actually tell you if you are sharp or flat. But your ear will! I would highly suggest you buying a tuner for your phone or buying a physical one as well. Tuners help you sound good!

Online Metronome - A metronome is a must! This thing is never wrong and it will help you so much. Practice with a metronome consistently and you will see lots of growth. Start slow and slowly speed up. This one is very basic. I really suggest you getting one for your phone that can pick specific tempos and subdivide.