Thanks for your feedback!
We only have 4 packs which are unavailable for purchase, these are the Donator pack and the Forum Challange #1, #2 and #3 packs. We believe these packs are small, but also a good addition to the software, but if we wanted to price them we’d need to do so in a relatively cheap way, which, considering all deductions from different payment options wouldn’t necessarily worth doing. On the other hand we wanted to keep a few, smaller packs out of the buying zone so to speak, so we can incentivize completing achievements, inviting friends and buying bundles. But fear not, we are actually in the process of adding 4 new achievements to the Profile section, so you might receive a few additional packs soon in case you’ve already met the criteria for them, and use those packs to claim the ones you’re still missing from your collection.