I am using Drupal 8, and I am wondering how I can clear more caches than the button in admin/config/development/performance does.
I have had trouble with installing Drush, so I am looking for any alternative solutions.
Just execute core/rebuild.php.
As the documentation says, it rebuilds the cache even when Drupal doesn't work; it require a token you can generate with scripts/rebuild_token_calculator.sh, so you call it as http://example.com/core/rebuild.php?token=TOKEN_YOU_GET_FROM_THE_SCRIPT.
Check out Admin Toolbar for Drupal 8, it emulates all the dev functions from a drop down menu like we had in Drupal 7 from Admin Menu. Be sure to activate "Admin Toolbar Extra Tools" as part of the module.
That button clears all caches, just like drush would.
The only alternative to that would be to clear the caches directly in the database, which isn't much convenient.