Tengu with wings. Oni All of the types from Pathfinder Bestiaries plus any others you might think up. Armored knight riding a rhino This was done by Ral Partha several eons ago, but the rhinos were not properly in scale. War machines Ballista, catapult, trebuchet, cannon. Carts, wagons, draft horses. Chariot and horses Room in the chariot to place a mini in it. As long term projects: Pathfinder Iconics Sex reversed, so that there is a male sorcerer, male brawler, female fighter, female wizard, etc, etc, etc. Pathfinder character races All of them, covering several different classes for each.
I'd like to see ninjas, both modern and futuristic. More dwarves like the one with the multi-barrel gun. Civilian sci-fi ala Firefly. Plenty of sci-fi marines, both riflemen and support weapons, plus a squad leader and a platoon leader. Fu Manchu and his minions and other pulp characters. WWII Japanese. 1930's era Shanghai: opium gangs, white Russians, Chinese warlords and their troops, European/American sailors, missionaries, Japanese soldiers, etc. 21st century SEALs/Special Forces. That is a lot of very different minis. If I were to narrow it down, I would say the 30's era Shanghai, since that seems to be the area that has the least coverage from other manufacturers.