In Digimon Adventure 02, Cody Haida & T.K. Takaishi are partnered with Armadillomon and Patamon respectively. Because both Digidestined are lacking crests, when Armadillomon Digivolves into Ankylomon and Patamon into Angemon, they must DNA Digivolve together to reach the Ultimate level, forming Shakkoumon.
Digimon Pendulum Z and Digimon Brave Tamer give us some extended evolutions of Shakkoumon in SlashAngemon or Vikemon. Unfortunately, only Paildramon obtained the power to Digivolve further over the course of Digimon Adventure 02 so we never got to see this happen on-screen. Personally, I was hoping it would happen in Digimon Adventure 02: The Beginning but instead they just told us all to throw away our Digivices and buy the new iPhone cases instead.
In the Digimon Adventure 2020 reboot, Patamon gained the ability to Digivolve into Goldramon. I like to think that, given the first Adventure 02 movie showed Patamon's Mega level form as Seraphimon and Gatomon's as Magnadramon, while Tri showed Gatomon's to be Ophanimon, Patamon would have access to Goldramon too under similar circumstances.
The Digieggs of Knowledge and Reliability enabled Armadillomon to Armor Digivolve into Digmon and Submarimon. If Cody had used TK's Digiegg of Hope, Armadillomon could have Digivolved into Sheepmon.
Without access to the Crest of Hope, TK had to use the Digiegg of Hope to Armor Evolve Patamon to Pegasusmon. Borrowing Cody's Digiegg of Reliability might have enabled Patamon to become Mantaraymon.
