A 150gal is just begging for some Denison Barbs. They'd work well with your stocking consideration. It's a Peaceful, active, graceful, gorgeous barb that unlike most barbs, does fine in smaller numbers. Figure as little 3 would make a nice small shoal.
75g Planted Barbs Denison, BlackRuby, Tiger, Albino Tiger, Green Tiger, Cherry, Gold, Checkered, Odessa.
NonBarbs Cardinal, Neon, RummyNose, Bloodfin Tetras, Z. Danios. 1RTS. Amano, Bamboo, Ghost & RCS. 20g Long Shrimp Tank RCS, Tiger, Amano.