Cards that spawn absolute mayhem upon the board of EDH.
Taken into account are all five colors to sustain WUBRG madness with Golos or other commanders that don't give a damn about colors.
Most of these cards serve no winning condition directly and without detours contribute to having no gameplan as in "Not for me and not for anyone else".
While some groups might find certain cards upsetting, detestable, vertiginous or revolting, you will never play the same game of magic twice using just a handful of these cards.
If land destruction is forbidden in your playgroup, change that. Chaos decks are fun and if they don't actively try to win, you are really just spicing up your playgroups adventures with a little unpredictable madness. Magic and especially EDH is about fun after all, weird cards are exactly what you want.