Where the promo cards come from
Cybernetic Walrus invited players to design new Critkin for an art competition. The developer announcement says the selected designs would become collectible promo cards. The Steam store page now lists exclusive promo cards from that community competition among the full game features.
The art-competition announcement and later fan coverage describe nine selected designs. Steam itself does not print a number on the store page. Nine is therefore the figure from the developer announcement rather than a count shown in the game listing.
How many promo cards there are
The Promo Collector achievement asks you to slot all nine promo cards into your collection. That achievement text lines up with the nine designs from the competition. Treat nine as the target when you plan your binder.
Promo cards sit inside the wider 1,809-card total rather than on top of it. They belong to the same CritDex as the 209 unique Critkin. The card list guide on this wiki explains how that total breaks down.
The two promo achievements
Promo Shopping unlocks when you buy a rare promo card. Promo Collector unlocks once all nine promo cards are placed in the binder. Achievement trackers show both being earned by a large share of early players, so neither is treated as a late-game wall.
Because the first one is a purchase, keep some cash in reserve once promo cards show up for sale. Selling duplicates is the steadiest way to build that buffer. The money guide on this wiki covers duplicate sales and the piggy bank.
What is not confirmed yet
The official material does not publish a drop rate or a fixed price for each promo card. This guide does not invent a shop rotation, a code or a probability. Check the developer's Steam announcements if a later patch changes how promo cards are sold.
Promo cards are also not redeem codes from outside the game. No website, including this one, can hand you a code that unlocks them. Ignore any page that asks you to download a tool to get promo cards.
How promo cards fit your collection
Promo cards share the binder with every other card, so placing them also counts toward full completion. That matters for Defy the Odds and the other collection achievements. Leaving one promo slot empty keeps the binder short of the finish line.
If you are chasing rarity, the rarest cards guide explains how promo cards compare with rare and mythic categories. The Critkin guide shows how each creature fills several binder slots. Together they help you decide which gaps to close first.