Gutenberg Library Replacement
The Gutenberg Library block allow the insertion of a predefined set of blocks to make building pages easier. It is defined in it’s own plugin: wp-content/plugins/uwss-gutenberg-library
I was planning to replace this with the Block Patterns functionality released with WP 5.5. https://make.wordpress.org/core/2020/07/16/block-patterns-in-wordpress-5-5/
I think it will be pretty easy to set up the block patterns, but I’m not sure how removing the library block will work. It might be fine because the library block is really just a container, but it may cause some errors.
It is possible to create a deprecated version of a block, but I’m not sure about how to deprecate it completely.
I do think it is worth trying to figure this out because I have had problems with the Gutenberg Library block breaking with version updates in the past.