The number "84,000" is only a figure of speech in Buddhism and it simply means many. As for the "illnesses of the mind" you can find the different abhidharma works that list the unwholesome dharmas, and another popular source in East Asian Buddhism is the Surangama Sutra's fifty skandha demons.
"If the Buddha-Nature is seen, there will be no seeing of a nature in any thing."
(Nirvana Sutra, T12n374p521b3; tr. Yamamoto)
"Neither cultivation nor seated meditation — this is the pure Chan of Tathagata."
(Mazu Daoyi, X1321p3b23; tr. Jinhua Jia)
"With sudden enlightenment to Tathagata Chan,
The six paramitas and myriad means are complete within that essence."
(Yongjia Xuanjue, T2014p395c14; tr. from "The Sword of Wisdom")