“ After particularly intense storm, a green glowing fungi can be found on the trees and plants. Also new monsters seem to be in the region. These storm are obviously bringing these things from other places and depositing them with the wind, rain, and goop upon the land.”
“ Have a large room that elevates either up or down when triggering a trap. The floor can bring the players to new levels, where a mighty beast roams, or the floor flattens the players into the ceiling or drop into a pit of lava.”
“ A casual remark by one of the party about something met on a previous adventure leads to a summons to and grilling by the Mages' Guild (or equivalent), probably resulting in an expedition back to that area to recover the things for study by the Guild. The party's presence will be 'requested' for this expedition.”