From personal experience, I think the best April Fools jokes are ones where
a) you’re not targeting a single person
b) are not cause of any (even unintentional) physical harm

The best one that was ever played on me was a colleague making us believe he had won the lottery and he was inviting us all to dinner to celebrate. It worked very well because he was the last one we would suspect of pulling such a stunt.

It was a good prank because it was aimed at whoever was around and we just all felt a bit silly as a group, instead of individually. It also did not cause any material damage, physical pain or great effort for anyone.