I'm really excited to see projects like make containerized applications more available. There's a lot of awesome new projects in this space and I'm hoping that we as a community can come together and adopt a standard API for compatibility across all tools. CNR[0] is the name of the effort that is essentially extending OCI[1] to support apps (Helm, KPM, Kubernetes, Docker Compose, Docker DAB).
https://cloudron.io/store/index.html is another app registry but meant for prepacked instant deploy apps (and not infra like nginx). I have been pushing them to use kubernetes or swarm to scale their offering.
[0]: https://github.com/cn-app-registry/
[1]: https://github.com/opencontainers/image-spec