The plants that grow from Mystery Seeds, Surprise Seeds, Jackpot Seeds etc are randomized, meaning there is no predetermined mix of plants that you will get.
A quick reassurance - most of us in the office have a farm and play it to see how it feels, and one of the biggest things we notice when playing is that when you are PURPOSEFULLY looking for something, it seems like it can't ever be found! It's like watching a pot hoping it will boil faster :)
We can assure you that there are lots of awesome plants that you can get from Mystery Seeds, Surprise Seeds and Jackpot Seeds! To back this up, keep an eye out on the fan page, as we will periodically give away these seeds!
Pro Tip: Pot Farm Pros keep a Munchie Garden on hand so when Quests call for specific plants you will have them ready!