Building URL Aliases Based on Specific Conditions

Have you ever needed to generate URL aliases for an entity based on specific set of conditions? I was recently on a Drupal 8 project that needed the ability to generate custom URL aliases based on very specific criteria outlined by the client. Out of the box, Pathauto module was not flexible enough to handle the customization, but leveraging its API and providing my own hook implementation in a custom module allowed me to perform conditional checks on data and build the conditional URL structures.