Okay, the first idea would involve 02-esque entrance and egress of the Digital World, and likely the formation of the Royal Knights for the first time. (Don't worry, any compatible Mega can be a knight.) There will also be something akin to Biomerging, although there will be a stand-in Mega and a true Mega which the Digimon get when they find some sort of associated weapon. The team would be aided by an organization within the Digital World.

Alternately, I've wanted to try something where the Digital World is a galaxy, and the chosen Digimon are somewhat related to constellations, either of the Real World or Digital World. So Digimon in Spaaaaaace!

Next, a bit of a legacy idea from old-guild (Forgot the original user or I'd credit, though I did try something similar) would be something like a Super Sentai thing, where Digimon can't maintain themselves well in the real world (without causing problems), and thus their partners manifest weapons (and themed armor) based on their forms/techniques.

And, two ideas based on the tactical reclaim of territories within the Digital World from dark forces, either through a standard team, or a team with the ability to Digivolve one Digimon in multiple ways.
If those don't work, I'm open so suggestions, and can probably come up with something else.

Speaking of which, themed Digital Worlds could be fun, like a fantasy world run by Digimon. Or, we could mess with some things and try a film noir esque detective thingy involving a mysterious Digital Incident.

If anyone has questions or suggestions, I'm open to them.