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.
"While teachers of the middle way, mind only, transcendent wisdom, mantra, and other schools may have their own assertions, the fulfillment of those intentions is the same. There is not a single thing that is not contained within mind."
(Gampopa to Düsum Khyenpa, in "The First Karmapa", KTD Pub, p254)
“If you recognize the world of appearance and existence as the mind, realize the mind itself as empty, and have no grasping at the superiority of your realizations — this is the ultimate view."
(Chegom Dzongpa, in "The Book of Kadam", Wisdom Pub, p609)