I was reading through the forum posts, and I noticed a lot of users were wishing for more colors.
The micro:bit onboard LEDs only come in red, but I wanted to make sure everyone realized you can control their brightness.
The display.set_pixel() function takes three parameters, with the last one being a brightness value 0-9 (0 is off, 9 is maximum brightness).
As one quick example, try running the following short program on your 'bit.
from microbit import *
column = 0
while column <= 4:
row = 0
while row <= 4:
display.set_pixel(column, row, 9-column)
row += 1
column += 1