huh, the [diceroll][/diceroll] can't be inputted manually, neat anticheat
and by my newer tests it seems your system isn't happy displaying 0 as a result of 0 dices and also not that euphoric to show negative values, which in my opinion ought to be inputted as [-1d1] and shown as *dice pic*[-1d1 = -1]... perhaps in blue(000088)?
mainly due to the positive=red, negative=blue that magnets have, and the following quite likely will be read as dumb, but could you make it so that either/and a [0d*any number here*(with perhaps a + or -999999)] or a result of 0 has the color 008800?
im mainly saying this because if + is 880000 and - is 000088 that leaves 008800 unused, and that slightly bothers me, but its completely fine if you don't... and to sound greedy on top of dumb(although im quite certain that i have gone WELL beyond the line of what is palatable to request with the following), how about a completely random dice? as in random +/- dice amount, dice digit and +/-0 to 999999 with the rainbow shift of >>6180
as it's color? as for the syntax, how about [rdr&r](which could stand for RainbowDashRoll) and the obvious variants of [rd1&1], [1dr&1], [1d1&r], [rdr&1], [rd1&r], [1dr&r])?, the "&" is to randomize the addition or subtraction since [rdr+r] or [rdr-r] might be wanted, and to be fancy the 6 variants that aren't [rdr&r] could have color shifts based on the other mane 6(+spike?),
and the other 47 variants(iv'e counted them and put them out in a diagram, im sorry) could have color shifts based on other ponies(perhaps 7 of them to the filly gang+little league????)
here is the full unique random dice combination diagram, again sorry for letting my stupidity flow
[rdr&r], [rd1&1], [1dr&1], [1d1&r], [rdr&1], [rd1&r], [1dr&r]
[rdr+r], [rd1+1], [1dr+1], [1d1+r], [rdr+1], [rd1+r], [1dr+r]
[rdr-r], [rd1-1], [1dr-1], [1d1-r], [rdr-1], [rd1-r], [1dr-r]
[+rdr&r], [+rd1&1], , , [+rdr&1], [+rd1&r]
[-rdr&r], [-rd1&1], [-1dr&1], [-1d1&r], [-rdr&1], [-rd1&r], [-1dr&r]
[+rdr+r], [+rd1+1], , , [+rdr+1], [+rd1+r]
[+rdr-r], [+rd1-1], , , [+rdr-1], [+rd1-r]
[-rdr+r], [-rd1+1], [-1dr+1], [-1d1+r], [-rdr+1], [-rd1+r], [-1dr+r]
[-rdr-r], [-rd1-1], [-1dr-1], [-1d1-r], [-rdr-1], [-rd1-r], [-1dr-r]
the 9 "missing" are because it's as unnecessary to mark a regular number of dices as positive as it is to add the random dice, if i'm honest, but i might as well request.