Dean isn't really in the best of pranky moods, so he basically just texted Sam pictures of clowns throughout the day, and maybe something harmless to Ben (or WITH Been TO Jules) because what else do you do with your kids on April 1st?? No specific ideas, I am bad at pranks, so.
Loki spent a good part of the day making certain people see things. Nothing scary/bad, just like little orbs of light, or bugs, or etc. These certain people are Thor & Tony Stark, because he enjoys poking at them.
Jaina angsted because today reminds her of Gabriel, and if things were not all kinds of screwed up with her family situation right now there would be pranks in his honor but oops.
Kat is also not really in the mood, but enjoys screwing with people, so she just did a Kat equivalent of the 'ding dong ditch' thing. Aka she beat on the door like SOMETHING WAS HORRIBLY WRONG and then teleported far away before they ever got to the door. This happened to pretty much everyone in Piffy's complex, and the main complex, and random people she didn't even know because she is trying not to wig out yaaaay.
Sherlock has no interest in this day but Joan got him, so he decided to lace all the drinks in his house with embalming fluid. This is mostly only going to affect him since who is even going to trust him with beverages anyway? But whatever, he feels he has accomplished something. If someone happens to drink something, it'd probably just taste pretty weird, and he'd be like HAH and ...then wander off, who knows.
Also, John, you got the honor of waking up with Lestrade staring at you. Good morning!
I think that is all, for mine... If I come up with something else, I'll update!