Is it possible to design our own card games?

Definitely can! But it must be well planned, especially if you wanna make money out of it :)

There is this guy who design coding card game called Potato Pirates and successfully launched it on Kickstarter back in 2017. They opened up the recipe and described how to design card games. You can read through it here. It's insightful!

Yes! There are so many ways you can make your own. You just have to be creative, it's like art