I actually think hornwort is pretty, especially if it's the only plant and you're not going crazy "aquascaping" a tank. In low light it might lose its little needle-like leaves and it makes a HUGE mess! You can try it out, because it's really cheap, but if it starts yellowing throw it out before you have a mess on your hands. If the tank also gets sunlight it has a better chance of living.
Also, anacharis/elodea might grow too. I had some in a little 1-gallon with no extra light, it wasn't even next to a window, and the plant still grew, even put out side shoots and rooted in the gravel. It's also a cheap one, so you won't lose a lot of money if it doesn't work out.
With the Cryptocorynes (aka Crypts), they will grow in low light but they can be fussy. They seem to rot for no reason sometimes, which can be annoying. They will bounce back though, so don't throw it out if it loses leaves.