1: No racism of any kind. Dogwhistling blah blah. Perma-Ban with no ability to appeal.
2: No griefing, stealing, destroying things that aren't yours.
3: No politics, cause chances are I don't believe what you believe and Id rather us just play Minecraft.
4: No cheat mods. (xray, killaura, etc).
4a: Map plugins, as well as plugins like optifine are perfectly ok.