red.

Zechariah 1:8
I looked out into the night and saw a man riding on a red horse that stood among the myrtle trees in the hollow. Behind him were red, sorrel, and white horses.

Revelation 6:2-5
So I looked and saw a white horse, and its rider had a bow. And he was given a crown, and he rode out to overcome and conquer. . . .

Revelation 12:3
Then another sign appeared in heaven: a huge red dragon with seven heads, ten horns, and seven royal crowns on his heads.

Revelation 17:3
And the angel carried me away in the Spirit into a wilderness, where I saw a woman sitting on a scarlet beast that was covered with blasphemous names and had seven heads and ten horns.

black.

Zechariah 6:6
The one with the black horses is going toward the land of the north, the one with the white horses toward the west, and the one with the dappled horses toward the south."

Revelation 6:5, 6
And when the Lamb opened the third seal, I heard the third living creature say, "Come!" Then I looked and saw a black horse, and its rider held in his hand a pair of scales. . . .