“ Temple of some malign being invites you warmly and offers help (curing,needed spell etc) for some minor sacrifice . Sacrifices must be everytime bigger to work - up to living inteligent creatures. Maybe you pay some other price,too...”
“ The PCs find a strange helmet, when donned it will take control of that PC and speak and act trough him/her. It explains that it is benevolent and needs their help in a quest and that it will stop possessing the PC when the task is done. Great if a player is gone for a number of sessions.”
“ You've probebly heard of the real Thomas Hopkins, Witchfinder-General, who hunted down and hanged suspected 'witches'. What if there was a world/realm where magic was normal, and it was the non-witches and non-wizards who were hunted down and hanged as inferior beings?”