>>74439WarGreymon's Terra Force/Destroyer is described either as being a white dwarf star or as being as hot as one (I'd need to check to recall the exact terminology). Another WarGreymon fought and beat a Lucemon who was going to destroy their digital and human worlds/universes. Another case has an Agumon in one of the games who was capable of going from WarGreymon to Omegamon without a MetalGarourumon required as a fusion partner, though this might be cheating since Omegamon is a whole different ballgame. Then there are the Wargreymon X feats.
The Xros Wars anime featured an extremely limited in power WarGreymon and Examon surviving being in the threshold of dimensions and were capable of creating barriers strong enough to resist Bagramon. The WarGreymon and Examon DigiMemories could also create a rift into the Real World, and appear in outer space. They then float in space, and orbit Earth in a protective bubble allowing the cast some relative safety. In Re: Digitize, Taiga's canon Digimon is WarGreymon, so we can assume he uses it every fight. He was able to defeat the Chosen Children and Tamers of the past, defeated Apocalymon (apparently had the power to create a new world (multiverse) by covering it in darkness), Vitium (multiversal, but she apparently wasn't going all out), and many others.
MetalGreymon's offensive ability is explicitly equated to a nuclear warhead and weaker Digimon like Tankdramon explictily use mini-nukes as a form of attack. Powerscaling WarGreymon X (since he doesn't have that many direct feats) features him possibly having helped against Mecha Rogue who is multiversal, surviving scuffles against Omegamon (in fairness it's not known how powerful said Omegamon was), and a bunch of other stuff. A Digimon like Ebemon can instantaneously destroy planets and he normally evolves from Vademon. A normal WarGreymon X would be stronger than the normal Ebemon. There's ALSO the fact that the Greymon line ties directly to the Milleniumon line.
>>74440Most of the high tier stuff is in the games and anime. Adventure and Adventure 02 are the reason we have the Digital World being a higher domain beyond the Human World multiverse in the games for instance.