Yes! While there is no built-in tool for listing all available PPAs, Canonical allows users to upload details about their personal repositories through Launchpad. You can search for the name of either the package or repository that you are looking for. Run sudo add-apt-repository along with the Launchpad link to add a particular repository to your Ubuntu system, then refresh Apt by running sudo apt update.
Do note that because Launchpad contains user-submitted repositories, you need to verify the integrity of any of its packages and repositories that you will add to your machine.