What's with all the tetras...?
There's a lot of cyprinids that school well and will put even the great cardinal tetra to shame.
Barbus rhomboocellatus is a superb schooling fish that hasn't bothered any plants since I got them. They definitely possess a subtle color, but the edges of their scales are outlined in neon green. And they school very, very well. Their pattern too is very unique--at first it reminded me of the pattern on a ball python.
Microrasbora kubotai (M. sp. 'Somchai') is another awesome species with an excellent eye-catching yellow color. Here's a pic:
Sundadanio axelrodi comes in a few colors, all of which display the same iridescence as the cardinal tetra. Here is a picture of the green form:
Danio choprai is another one that schools very well and has very pleasing yet somewhat subdued colors.
Others that work really well:
They're all great, but I think the best school for a planted tank is by far Corydoras pygmaeus.