Back in 2018, I was working on the design of card games intended to be distributed digitally. Players would need to first print out the cards, then cut or otherwise prepare them.
As I wanted to understand the largest size deck that PnPers (Print-and-Players) had ever actually printed, I posted a poll on BoardGameGeek. Ironically, I now have responses from 54 PnPers (54 being the size of a standard four-suited deck of cards with two jokers!).
I provided choices in increments of 9, since 9-card sheets are very common. The vast majority of PnPers (81%) have printed out at least 37 cards, and three quarters have printed out at least 46-54 cards (76%), the size of a single deck. Most dedicated-deck card games are the equivalent of two decks, with 100-108 cards, and 46% of PnPers have printed out games with that many cards. Three out of ten have printed out three-deck games (154-162 cards), while two out of ten have printed out four-deck card games (208-216 cards).
The audience of those who will print out and play card games is already small. If you make your card game too large, you’ll have even fewer potential players.
Check out PNP Arcade for a rich collection of card games and roll-and-writes.
From my own designs, check out The Pearls & The Peril (9 cards), Hopping Halflings and Spin Rummy (each 18 cards), Melee in the Mines (36 cards), Axis & Allies Technology Cards (67 cards), Civscape (108 cards), and Colossal Cave Adventure Card Game (115 cards).