I can never find a good vanilla server. So I'm hosting this one on my computer. Use common sense to not get banned. This 100% vanilla I downloaded the .jar straight from minecraft.net.
The only command blocks are for... Suicide (If you can't find a cliff to jump off of), Removal of Rain (If it lags you), and Glow Effect (If you want someone to find you). A few others for protecting spawn from monsters, TNT, and YOU.
I made the commands unique, usually commands on a vanilla you type /trigger set command 1; but while off the ground you look straight up then the commands will appear in chat then you'll simply click'em to execute'em.