I only remember there being a green theme that I didn't like, and the default theme which I forget the color of.

There were less when I joined I think, but during one of the forum updates there were:

BGS (predecessor to the current Warrior theme), green, blue, red, tan, grey, and a different grey (or a different one, i remember there were two of one color, just different shades).

Then on the next update all the skins broke and there was utter chaos, and for a time there were two sets of skins because the old ones weren't removed (the old ones and then the same ones with a "_FIXED" IIRC)

I remember the 04's sneering about how the Green theme was the true theme and everyone on the tan theme were fools.