I made my own tools, which has been both fun and useful. I haven't put too much work in making them easy to use for others, but maybe they can help? The two that are polished enough to at least share are:

https://johanneshoff.com/sheet/ is for getting faster at recognizing note values in sheet music. I used this for about five minutes a day for some time and it really improved my reading. A musician friend of mine said it had limited use, since notes are always in context, and here it's just random notes. I think this is a good start, though, but the journey from there is probably some other tool.

https://johanneshoff.com/intervals/ to practice intervals. For this one I recommend a MIDI-keyboard and the 'meander' mode. Start out with just a few intervals and take it from there. I found it absolutely crucial to pick some songs that represent the interval. See for instance https://www.youtube.com/watch?v=PhDIm_2qS5s