Well uh, I stumbled upon this earlier today. I see that this is from Jurassic Unboxing, so I may have to do some digging to find out the origin of this image, but at least we know now what the sadly canceled (?) Dimetrodon set would have been in package (which is with the Compsognathus, not the Microceratus after all this time we were left thinking). There was a brief look at it at SDCC back in 2018 as well. Thought I would share this for anyone interested though.

I can't remember if I shared this already here or not, but another set I thought was canceled (this might be appropriate for me to post in the 2019 thread as well), is the Matchbox set with the Mosasaurus and Sea Sub. I know there was an image of what the set looked like at Toy Fair that Jurassic Outpost shared, but it turns out it is finally getting a release in Dino Rivals packaging and seems to have been popping up lately in some places (as a few have been for sale on ebay, though as one can guess, also overpriced).
A look at the original unreleased set:

The new version:
