Question: Do you know of a resource that helps musicians improve their ear training and recognize chords by ear?

For ear training and recognizing chords by ear, Hooktheory is well worth your time. It includes tools like Chord Crush, an interactive tool designed to help musicians learn to recognize chords by ear. Hooktheory also taps into data from thousands of popular songs, so it's good for musicians of all levels.

Another good option is ChordAI. This system uses deep learning algorithms to recognize chords and beats from audio sources like YouTube, SoundCloud and audio files. It comes with a chord dictionary that shows chord diagrams for different instruments and can infer the key of a song based on the chords it detects, so it's a good all-purpose tool for musicians who want to train their ears.

Moises also has some useful ear training abilities, including real-time chord detection and pitch shifting. That means musicians can practice music in any key and tempo, and it's a good tool for drummers, singers, bassists, guitarists and producers.

If you're looking for a broader range of music production tools, Fadr offers a collection of AI-powered music tools. That includes a key/tempo/chords detector and stem extraction tools. That can be useful for musicians in a variety of creative music production situations, from splitting songs into their component elements to creating remixes.