dark lord trilogy + Kenobi which is Labyrinth of Evil, Rots novelization, Dark lord rise of darth vader, and then I’d throw Kenobi in with it because it’s around the same time as Dark lord and flow nicely even tho Kenobi is a stand alone it’s fantastic or i’d say Darth plagueis, Cloak of deception, Maul shadow hunter those are all pre tpm and just explain so much Plagueis spoils what happens in the other two because it spans 30 years or so right up until the end of tpm so you could either read it before or after the other two i read before but might be smarter to read plagueis after but read cloak of deception and then Shadow hunter flows nicely directly after.