United is planning to unveil new routes tomorrow. They dropped some hints on their twitter.
There was a pretty big rumor going around that KDEN would get a new route because Scott Kirby (President of United) recently said so in an interview.
For these routes I think they are:
San Francisco - Amsterdam
Newark - Naples
Newark - Prague
Not sure what is going to happen in Denver but these routes do look like they make a lot of sense.