Here’s a link to the Youtube playlist by Andy Mullen about TONAL LESSONS. Each are only a minute or two, and there’s about 20 of them. They are in the same ballpark as IFR, with the main difference being that Andy Mullen uses solfege instead of numbers to name the tones. https://www.youtube.com/playlist?list=PLXfcUvl7qzNyXTJlcxMaz6sUwkmcU7I-Q
There’s a companion set of RHYTHM LESSONS here https://www.youtube.com/playlist?list=PLXfcUvl7qzNyZjeaFfJ_pe_LdhNQ8rxIX
Furthermore, Andy Mullen has lots more interesting playlists of Youtube videos on topics dealing with musical foundations, all based on the work of Dr. Edwin Gordon, all of with supports and complements IFR, although sometimes with different terminology.