The first part of this story is the listing for the World's Smallest Transformers over at DeepDiscount.com. It appears listed as World's Coolest Transformers but is specified as World's Smallest Transformers with the current details:
Brand: Worlds Smallest
UPC: 810010990204
Item #: 2162551X
Available Date: 7/31/2019
Model Number: 587
List price $13.00
Then over at TheToyBook.com we have some nice images of the upcoming products from each of the above mentioned properties. The article states from Transformers we can expect Optimus Prime, Starscream, and Bumblebee. From G.I. Joe we'll be getting Snake Eyes, Duke, and Roadblock.
Although there's not specifics on which Power Rangers we will see the image provided does show the Yellow and Pink Rangers from the original U.S. series along with a note about the card backs listing product name placeholders. The card back itself appears to be from the Ninja Steel line of Power Rangers. Although not clear on all images, the power ranger image in the foreground does specify these as key-chain action figures.
Each of these will be an articulated figure on reproduction card backs, which for Transformer fans will no doubt be a big part of the appeal.
Enjoy the images and as always share your view with the Seibertron crew in the forums!