For now, the easiest way would be to click on the main menu (on the left). For example, when viewing the Post list table you can click “Posts” and this will reset all filters.
We know this is not very intuitive. So we have been working on one “reset filter/sorting” button. And it will be released later this year, but we are including it with an update we are doing on filtered segments. This new feature will save all filters as a user preference. When a user returns to his list table it will be exactly filtered and sorted the way the user left it. This will make the “reset filter” almost mandatory because it would be very cumbersome to remove each filter manually.