Here is an online metronome you can practice with.
Practice sight-reading! This website will help you get more proficient in sight reading. Set the difficulty on Level 1 and change it as you get better.
Fun way to practice fingerings for your own instrument and naming notes.
Learn to play jazz on this website. This page will help you understand how jazz musicians approach their music.
These two websites contain fun ways in which you can practice your music theory and expand your ear training.