I just saw this on WP Tavern and noting it here for the future.
With Gutenberg you can make reusable blocks. The neat thing about them is that if you subsequently edit the block, you change it for every appearance on the site. That can be handy if you need to update some information contained in the block.
The tip on WP Tavern was that if you want to see the reusable blocks you have made, log in to the admin panel and then add the next bit and you will see them listed.
Change One Instance Of A Reusable Block
This is something I heard tonight at a WordPress Meetup. If you want to use a reusable block and keep most of its features but change it a bit for just one instance, you could just start from fresh. But another way to do it is to duplicate the reusable block; change the duplicate to a standard block and then edit it. Then delete the reusable block.