from what I can see at https://fediblackbook.com/ their API is "here's a URL with a list of accounts to block"
you can write a program that takes those values and calls the blocking/create
or mute/create
to block/mute that remote user for one of your local users
or you can use admin/suspend
to suspend that remote user (so that no activities coming from that user will be accepted by the local instance)
notice that in all those cases you may need to hit users/show
to make sure you get the local userId
for each remote user
you can get some documentation on the misskey/sharkey API by going to the /api-doc
page on your own instance