On search, folder, and library page, when a user clicks “select”, after version 7.4, multi-select is finally supported, however, there is no select all function.
Please support select all by adding a button.
On mac, please adopt cmd + A shortcut for this feature.
On mobile, please adopt Apple’s native two finger swipe gesture for multi select. You can try this in Files, etc.
Use case example: adding 300 Tom and Jerry episodes to a playlist from folder or search.
We need a feature to select all files in iOS. For example, I want to select all files in my webdav folder and make a playlist but that is not possible. I have to select one by one which is tedious if there are a lot of episodes
I moved your post to a currently running thread requesting this feature.
Don’t forget that you need to click the like button on the first post in this thread to show your support for this suggestion! 
I have organized my Looney Tunes into folders by character on my NAS. I thought it would be easier to make character collections this way. And while it is a bit easier to go to files, navigate to a folder, and then use multi-select to add them to collections, clicking hundreds of titles one by one is tedious!
How about a “select all” button when the select mode is enabled? And dare I suggest a “Create collection from folder” option???
This is really needed.
Tell me about it! My 56 custom collections somehow became corrupted and were displaying 2 versions of every title. I had to delete them all. I’m not going through and creating them all again title by title!