VR Digimon were created by ZeedMillenniumon as to finally defeat Ryo and ENIAC. The only difference between them and normal Digimon is that they have red eyes. VR stands for Virtual Reality.
They were controlled by dark clones of Taichi (Tai), Daisuke (Davis) and Takato. Each controlled three VR Digimon.

Dark Taichi
Dark Taichi controlled: VR-Omega, VR-Apocaly and VR-WarGrey which are Omnimon, Apocalymon and WarGreymon respectively.
Dark Daisuke
Dark Daisuke controlled: VR-Imperial, VR-Venom, and VR-BlackWarGrey which are ImperialdramonPM, VenomMyotismon and BlackWarGreymon respectively.
Dark Takato
Dark Takato controlled: VR-Duke, VR-Sakuya, and VR-SaintGalgo which are Gallantmon, Sakuyamon and MegaGargomon respectively. After defeating all three of Dark Takato's VR Digimon, VR-Duke will Digivolve into VRC-Duke , which is a VR of Gallantmon Crimson Mode.
Sources
- Pic from http://www.syldra.net/yesterday/