Packaging for Bootc Images

Recently bootable containers (aka bootc) have gained significant interest for deploying and reproducibly build linux systems. Projects like ublue use this technology to build on top of standard Fedora images and add stuff on top. Luckily, they also make it easy for anybody to create your own image further downstream (see their Image template)

What is the problem?

As mentioned, this all builds on top of Fedora and their package repos. Any package contained within these repos can be easily added to your own image. However, this changes if it is not packaged. Where to get them then?