Yep, I've found this to be the case as well. Luckily Disc Golf World here in KC is great and will let you search through their stacks in the warehouse to find what you want. But you gotta search for the odd gummy ones. I don't think it's any particular runs, but just kind of hit and miss as to when you find a gummy one.
I found a bubblegum pink leopard w/ blueish and white streaks that was the gummiest, grippiest plastic ever. Grip feels more like X-link or soft Vibram than any star plastic, but the disc itself is quite rigid. It feels great, but unfortunately for me flies like no leopard I've ever thrown. It's not a meathook, but it's more overstable than a champ teebird. Obviously not what I was looking for in a leopard, so unfortunately it never gets thrown.
On a related note, I've asked this in other threads but never saw an answer. I know that mids like the mako and roc are all in a softer grippier blend of star than normal. They're not gummy, but much softer than what I've felt in any other star plastic. Does anyone know if other molds are being molded with this plastic as well? I could really get down with a teebird or leopard in that blend, but I don't know if it's exclusive to the mids. Any info is much appreciated.