Remember that in Legendary Collections, common cards are often harder to pull than foils, since there are so many more of them for a single pack to pull from. There's also the possibility that this may be Short Printed, and so we could be looking at quite the expensive card. I've also found a picture of an Ultra Rare Harpie's Pet Dragon from the set:
In other news regarding the set, I've noticed that Konami's article to announce the release of Sixth Sense also mentioned that it will not be the only previously unreleased card in the set:
Harpie Dancer, anyone? Stay tuned for more news regarding Legendary Collection 4: Joey's World throughout the week!
Edit: Found pictures of Secret Rare Sabersaurus and Kabazauls. Only 23 months after the TCG release of Rescue Rabbit, no big deal.
There are also pictures of Secret Foolish Burial and Scapegoat, Ultra Book of Life, and Super Super Rejuvenation on this Facebook page.