No jerks. Be excellent to each other.
No real-world politics. This includes venting frustrations about how "woke" 5E or other systems have become. Reminiscing about the Satanic Panic is okay.
DCC both celebrates and pokes fun at the tropes of pre-1980s sword and sorcery, so it's good to have a sense of humor about that sort of thing. If that's not your style, that's okay, but this game probably isn't the right game for you.
DCC contains "metal" elements like characters forming pacts with demons, bargaining with elder gods in strange dimensions, and semi-graphic critical hits. PCs are absolutely allowed to participate in all of those things. If you find any of those elements offensive, this isn't the game for you.
Character death is very likely in this game. Players should be comfortable with that idea and, if the worst happens, be ready to roll up a new character and jump back into the action.
All that being said, we're going to try to exercise good taste in this game. The idea is to evoke the feel of Appendix N, not Game of Thrones.
My hope is to draw a diverse group of players who just want to relax and have fun together. As long as you're okay with the rules above, everyone is welcome.