Good API/3rd party site for tutor?

Welcome!

I know of no such plugin, but if none exists here is what I would do:

Do you need them to know of what you’ve learned so far or what you are struggling with (ie what is sticking around as an apprentice and what not)? If only the former, then they could probably look at what is tagged for your level on a chart like one of these:

I presume by adding or removing stuff from the practice pool you mean remove stuff that WK already covers from the practice pool which they have for you. There are 10k lists that suppress WK content that might be of interest to you: