Here's the video Disney posted that highlights all of their May schedule:
No sign of Disneyland Goes to the World's Fair unfortunately. It'll probably be pulled from the schedule just like Man In Space and Mars and Beyond were. Too bad, because I'd totally check out those old specials from the 1950's and 60's.
Good news: there's a brand new Pixar SparkShort coming on May 22, called Out. Definitely the big surprise in that video.
Other than that, it's pretty much what we already knew: Star Wars, Maleficent, some new original shows, a decent helping of both more NatGeo and Disney Channel content added to the library, etc.
Here's a poster for you to look at:
The UK is also getting some stuff in May. Besides the usual originals, they're also getting:
-The Rise of Skywalker on May 4, along with season 1 of Star Wars Resistance and Lego Star Wars All Stars
-Lost Treasures of the Maya (season 1)
-Percy Jackson and the Lightning Thief
-Bizaardvark
-SparkShorts Loop and Out
-Marvel Rising: Battle of the Bands, Operation Shuri, and Playing With Fire
-Marvels Future Avengers (Season 2)
-Night at the Museum
-Zenimation
Plus more. Check the whole list here:
https://disney.co.uk/everything-new-coming-to-disney-plus-in-may
What the heck is Zenimation? No clue, but apparently it's something new from Disney. Could be yet another new original. Could also be a misprint that wasn't supposed to be on this list.
Australia/New Zealand are also getting some unique releases:
-101 Dalmatian Street
-season 2 of Star Wars Resistance to go along with Rise of Skywalker on the 4th
-Time Scanners season 1
-Maleficent Mistress of Evil
-TOTS season 1
Plus a bunch of the common releases that both the US and UK are getting, of both originals and older Disney material. Whole list:
https://whatsondisneyplus.com/whats-coming-to-disney-in-may-australia-new-zealand/