Mostly just out of curiosity.
I have seventeen.
Four for reading status:
Currently Reading (includes the immediate TBR list),
Pile of Shame (yearly backlog),
Unread, and
Read.
I have five more for the type of book:
Fiction,
Fanfiction,
Nonfiction,
Magazines & Publications, and
Documentation & Manuals. I used to have one for Comics, but later merged it (first into magazines, then into fiction).
Then I have:
-
Series
-
eBooks
-
Physical Books
-
Purchases
-
Loans (I don't keep the books myself, just records)
-
On Device
Then the last two are
Recently Added (in the last 30 days) and
Cleanup (mostly used as intake, but sometimes older books get flagged and end up here until I fix various issues).
A lot of my VLs also have an associated View Manager views because I use a
lot of custom columns for different purposes: