Black Lotus and Ore can easily be found in Austrilund and Nordrilund, Wintertusk (Grizzleheim). They are also found in Cave of Sollitude, MooShu. The Ore/Diamond near the teleports/water area, the Black Lotus on the grassy parts.
if you garden. frozen flytraps give diamonds. king parsley can give diamonds and sun stones, though he usually just gives bad pet snacks. I think burning snap dragon can give black lotus, however, it drops so many different reagents that this is not at all reliable.