I've made a tool to help other people create their own Adventures. You can find it at https://customkeyforge.github.io/cardbuilder/. What does it do?
Create your own house by defining three colors and an icon
Save the entire adventure (including rules and card art) to a JSON file, to easily save and reload it later
Export the entire deck for printing as either PNGs or a PDF
Double Size Cards!
Set the default card back and override it on a card-by-card basis
Change tracking, so that you can print out only cards that changed recently.
Creating a Keyforge Adventure is a great way to try designing your own game modes. You should give it a try!