My favorite 'mind training' work is Shantideva's Bodhisattvacaryāvatāra. Technically this is not a lojong text but it always struck me that in purpose it most certainly is. I also remember reading somewhere that HHDL said something to that effect as well.

As for lojong, Geshe Sonam Richen's Eight Verses for Training the Mind is a great little book (I really like his translations).

B. Alan Wallace's A Passage from Solitude is an exposition on another core lojong text, Geshe Chekawa's Seven Points for Training the Mind.

Lojong (Tibetan Mind Training) - https://en.wikipedia.org/wiki/Lojong

Mind Training: The Great Collection translated by Thupten Jinpa - https://wisdomexperience.org/product/mind-training/ The comprehensive and definitive collection of lojong texts.

Essential Mind Training translated with introductions by Thupten Jinpa - https://wisdomexperience.org/product/essential-mind-training... A subset of the works from the above larger book. Read/buy this one first since it categorizes and introduces each topic before the actual texts themselves.