What would be good to add to my 45 gallon freshwater tank?

i have 2 dwarf yellow gourami. 1 male pearl gourami. 3 red Phantom Tetras.2 zebra danio. 2 leopard danio. 2 glow rasboras. 2 rummy nose. 1 .plecostomus but hes about an index finger lengh long. 2 black skirt tetra. 2 gold mollys. lots of plants. caves. etc. what can i add that would go wwell with all these?