Yesterday I wrote about the Note Identification tool at musictheory.net. That’s a great tool, but knowing the notes is only half the battle. You also have to know where to find them on the fretboard!
Assuming you have some baseline knowledge, this tool drills you on every fret of the ukulele. I’ve customized the tool with the link provided to set the Instrument to Ukulele and drill on 10 frets.
Use the keyboard so your mouse doesn’t slow you down. Hold the up arrow key while pressing the letter key to indicate a sharp note and the down arrow key for flat notes.