i think swords flower also... i could be wrong. if the runner is above water it will flower. i think hornwort can flower also but its rare.... thats all i can think of at this late time at night.
I don't know of any formula to get anubias to flower. When mine flowered last week the conditions were: 10 gallon tank, 2 10 watt compact fluorescents, Hagen CO2 system, a few drops of Florapride a day, and water changes once a week. Something I did do different was I split the rhizome to form two plants a while ago when I rearranged the tank. I believe it was the next thing to come up after along with another leaf. Anubias is one of the few plants that will flower under water, because it doesn't know a different.
Here's a few pics from the anubias plant before I cut it and then with the flower: