I have yet to see a good April Fools joke by a company. The whole concept is tricking somebody into feeling foolish. That part is easy. Doing it in a way that doesn’t irritate your customer or employee is hard. Why bother? Just do on April 1 the same job you do on April 2, and leave the pranks to individuals in their personal lives, not companies.
Sega released a whole visual novel where the player has to solve the mystery of Sonic's apparent murder. That was well received online, and got a ton of high review scores:
Many game studios release fake patch notes for April Fools. The IETF has such wonderful proposals as RFC 1149 (IP over avian carriers) and RFC 2324 (Hypertext Coffee Pot Control Protocol). These things are harmless and funny and make the world shine a little brighter.
Games Workshop did a pretty good one this year - which I enjoyed and think you might enjoy because what's funny is the absurdity of it, not that it makes a fool of anyone: https://youtu.be/uWgKkN4c1QI
