download Automation Blocks for Premiere Pro at https://aescripts.com/automation-blocks-for-premiere-pro/
see this forum discussion: https://community.adobe.com/t5/premiere-pro-discussions/montage-r%C3%A9p%C3%A9titif/m-p/14423297#M490886
Learn how to add an intro and outro to many clips at once in Premiere Pro. We use Automation Blocks to append an intro and outro to all selected clips automatically. The script we use creates a new sequence for each selected clip and in addition to the clip itself, it adds an intro and outro clip into the sequence, too. After running the script, all you need to do is adding all sequences to Adobe Media Encoder’s render queue.
