It's currently possible to paste up to 1,000 domains into the Personalized Results settings. Once they're saved, the only way to delete them is to click delete on each individual domain.
There ought to be some bulk management features to allow deleting some/all domains at the same time, and moving multiple domains between categories (block/lower/raise/pin).
There are multiple ways to implement this kind of functionality. Roughly from easiest to most difficult:
A reset button that removes all domains, or all domains within a selected category (e.g. all domains in the block category).
Checkboxes to the left of the domains to allow multiple selections, with a checkbox at the top to select all. Then buttons would appear to allow deletion or moving to a different category.
Allow grouping of domains into lists, and allow these lists to be added to different categories. This would essentially be most of the way to allowing users to subscribe to blocklists (like uBlacklist).
