Of course, there are some awesome tools out there to help you as a GM. This is an unordered collection, vote for your favourite ones in the replies below:
the infamous yxans klagan:
smoke raven has some really powerful tools collected, I’m especially amazed about this one:
For the ultimate number-nerds:
other Random generators:
Onepage dungeon generator:
https://perchance.org/fl-session-generator