hi, as icons limited by the font lib when the original production, so what icons you wanted maybe not in the lib. but there still have some options not included in the iconbox UI by this theme default, you can added them manually:
1. open file functions/pagebuilder/css/style.css, find class name begin with ‘s-‘ ‘p-‘ ‘pt-‘
2. open file functions/pagebuilder/pagebuilder-modules.php and find this:
array( 'id' => 'icon', 'item' => array( 'm-check', 'm-close', 'm-play1',...
add those class name you find in step 1 at the end of this array like this:
...'m-forum-top', 'p-play',... )