When filtering the list of tables in a database it only deals with tables currently visible without any way to access tables included in the filter results that appear on other pages.
1 Select a suitable database in the navigation panel
(Suitable is one that has many tables that will show with a suitable filter)
2 Find a filterable group that is big enough to require two pages
If this doesn't happen immediately, you may be able to change
"Max Items In Branch" to force it
3 Apply the filter
While the panel does display the number of tables matching the filter that
it hasn't shown, there is no way to reach these.
For example, in you database you have a whole load of tables called "MyWork_<something>", so applying the filter "MyWork" shows them to you. But, there are so many of them that they take up more than one page, either because they happen to start near a page boundary, or there are just more than one page worth of them.
This makes the table filter much less helpful that should/could be.
Sorry, that last but one para should read "BUT if there as so many of them that"... "then you can't see the others".
About step 3: You can access them by clicking on 'x other results found' link.
Inability to navigate between pages when the filtered table list spans more than one pages should be fixed with https://github.com/phpmyadmin/phpmyadmin/commit/17ab2ff6d443638b4eef05383979382e89221928