There have been two Bulborb species that were cut from the end versions of the Pikmin game.
Blue Bulborb
File:Bluebuborb.PNG
The beta creature.
In a prototype video of Pikmin 2, a small blue creature is visible. It is clearly a Bulborb with white spots. An adult version was never shown.
Yellow Bulborb
File:Betayellowbulborb.PNG
A large Yellow Bulborb.
Yellow Bulborbs also appeared in the same video as the blue ones. A dwarf version was also seen. These could have been later redesigned to Orange Bulborbs.
Both these colours match those of the three main Pikmin. Along with the Red Bulborb, each Pikmin type would have a fitting Bulborb.