Through time new Pepemon NFT events will come into play. These events will grant you guaranteed rewards as listed on the event page pepemon.finance/events. Examples of these are evolving a Pepemander into a Pemeleon or upgrading the quality tier of a trainer card. Entire battle card packs are going to be rewarded for those that hold Collector Edition cards.
If you see an event you’d like to participate in, but do not have the required NFT, there will always be a purchase option hosted on Opensea (an NFT trading website). If another Pepetrainer lists the item for sale there, you will be able to purchase it directly from them.