Honestly, I wouldn't mind Tamers and Frontier getting a revival series, since Tamers had interesting humans and Frontier felt... rushed and kind of incomplete.
I know a lot of people don't like Frontier, but I think if they finally fused both Ice/Wind/Thunder spirits and less lone wolf and goggle boy emphasis, it would feel like a better series. Plus show more Ancient Digimon or have the Ancients as alts or slides of DaiPenmon/JetSilphymon/RhinoKabuterimon. Plus IMO, kids should have been the Earth, Wood, Water and Steel spirits, especially since the Spirits of Darkness were used. Or hell, find a way to have Bokomon and Neamon acquire spirits and have humans, I mean, whose to say the kids HAVE to be the Digimon?
Savers/Data Squad could also have a sequel, where the kids are allowed to visit their Digimon once a year or so (seriously, that series' ending sucked!)
Which series do you want with a continuation?