Season 3 (Tamers) Enemies
The 12 Devas, Digimon from the Zodiac, were sent to the real world by Zhuqiaomon to capture Calumon. The Tamers defeated them all, except for Antylamon, who became Susie's Digimon partner.
Impmon / Beelzemon
Impmon was a harmless enemy, although he caused chaos in public. His pride was injured when he almost got destroyed by Indramon the horse deva, and vowed to become more powerful. In the Digital World, Chatsuramon the dog deva gave him the power to digivolve to his Mega form, Beelzemon, if he would defeat the Tamers. Impmon agreed and digivolved. He fought the Tamers, killed Leomon, and almost defeated everybody but was stopped by Gallantmon. Later, he changed his ways when his Tamers, Ai and Mako, apologized to him and each other. He digivolved to Beelzemon Blaster Mode and helped out in the fight against the D-Reaper.
The pheonix guardian Digimon hated humans and thought that humans and Digimon didn't belong together. He fought the Tamers, but later changed his mind and made up with the Tamers.
The D-Reaper wasn't a digimon, but a program made to destroy Digimon that grew out of control. It spread to the real world and endangered everything, but the Tamers defeated it by making it de-evolve.