What are the available hooks for views
They're here


In the codebase: core/modules/views/views.api.php.
On the web: https://api.drupal.org/api/drupal/core%21modules%21views%21views.api.php/8.5.x


As always, only *_alter hooks and hook_theme can be implemented in a theme. Any other hook needs to be implemented in a module.