There are service limits on the number of integrations, project deployments, connections, lookups, and JavaScript libraries you can create in a project. See Service Limits in Provisioning and Administering Oracle Integration 3.

To stay within the project deployment limit, delete old versions periodically. If you need to keep older versions for auditing purposes, you can export the project deployments and archive them using your organization's archiving tools, such as a source control system.

Lookups and JavaScript libraries are visible and usable only in a single project.

Your uncluttered view shows you only the assets in which you are interested.

Similarly, assets created in standalone integrations or integrations in packages are not visible or usable in a project.