More filter options on admin/content Is there a way to have more/advanced filters on https://example.com/admin/content using Drupal 8? Like filtering for taxonomy terms or fields for example?
Yes. Now that Views is integrated into Drupal 8, the admin/content display can be driven by a customizable View. 

Make sure the Views/Views UI module is enabled in admin/modules, then navigate to admin/structure/views. You'll see a View named Content which corresponds with admin/content. You can edit that view to add various exposed filters that correspond with your own content setup (e.g. custom taxonomy filtering).