When people have more disposable income, they're more likely to invest in hobbies, which can drive card prices up
Each of the 57 legendary creatures in Commander Legends: Battle for Baldur's Gate 30 uncommons, 25 rares, and 2 mythic raresappears in the rulebook treatment, as well as a selection of other non-legendary cards
Now lets explore some new cards
You can also use monsters your opponent controls to complete an Extra Link - if your opponent has 3 co-linked monsters in a row in their Main Monster Zones, summoning 2 Links to the Extra Monster Zones co-linked to those 3 will allow you to complete the Extra Link
This means there are hundreds of thousands of individual serialized cards out there, although some have smaller runs than others
Other editions can be valuable as well