How are words picked for the words event

Is there a list of words that are used for the random words events? Like do they use the top 50000 most common words for instance? Interested in making a piece of software to generate this

They used to pick words on random from a specific word lexicon (can’t recall which one), of which 80% should be nouns, 10% verbs and 10% abstract nouns (or maybe it was a 70/20/10 split?).

When preparing words for competitions in practice, I don’t think the words are always chosen from a dictionary, but rather thought up on the spot (while still respecting the 80/10/10 split). I was looking into doing such a piece of software once on my own, and the biggest problem I faced was to find (free, and big) lists of words with the accompanying word class. If you can find some lists like that and keep the split as mentioned above, it should be good enough.

If I’m not mistaken, there should also already exist at least two websites where you can practice with words that follow this type of split (Standard Memory and the IAM Training Page).