My Music Trainers
Two free trainers for musicians, both running entirely in the browser. Nothing to install, no account, no limit on how much you practise.
Why these two
Ear training and fretboard knowledge are the two things that stay awkward longest if you learn an instrument on your own. Both reward short, frequent practice far more than long sessions, which is exactly what a browser tab is good for.
Neither asks for an account or anything to install — open the page and start practising.