Think of a couple conspiracies and let the players try to understand who wants what; now you have at least a dozen conspiracies to play with.
A few sessions ago, the party thief, who had been wounded, went to see a doctor. The doctor couldn't heal her so she left without paying. The doctor sent mercenaries after her.
Today, the mercenaries finally caught up. A NPC the party saved last session offered to cover the mercenaries' expanses, provided the thief payed the initial fee.
The players spent most of the session trying to tie both the NPC, the mercenaries and a few unrelated rumours into a plot that may or may not exist.
We are an inclusive Mastodon community for everything tabletop (and more).