Practice Note Names - MusicTheory.net
Click on Settings to switch to bass clef or to alto clef (violas)
Practice Note Names, Fingerings, Music Terms - MusicRacer.com
In the blue box, choose note names, fingerings or music terms. In the yellow box, choose your instrument.
Then, on the lower left, click begin. It's a public site! If you get on the list for fastest times, use only your first name.