The only bright blue contacts that I definitely know can cover dark brown eyes and still look amazingly bright are the Princess Pinky Twilight Blue
from Pinky Paradise. Reputable company, reasonable prices.
I have dark brown eyes normally, this is how they look:
The pictures don't do it justice. They are a VERY bright bright icy blue, and even from a distance they stand out.
I wore those for my Elizabeth cosplay and they looked fantastic.