I have over 1000 books in the cloud, and by the time I get around to reading them, I have forgotten WHY I bought them!
Is there any way to add a short string to the book title as displayed in the library? (I primarily read on Kindle paperwhite, but sometimes on Kindle Fire or Android phone). For example, "funny YA fantasy" or "recommended by [x]". In an ideal world, this string would be searchable, but even just having the option of displaying it while scrolling through the library would be extremely helpful!
OK, this is probably *way* morw work than you want but in theory it is doable:
You will need a program like Calibre to edit the book's metadata and change the book description, the thing that pops up when you open a new book. You will then have to sideload such books and can no longer download them from your Amazon cloud as Amazon's version will override yours.
Since third party links are now not permitted, google for "edit Kindle metadata" to see how to do this and the issues it may present in terms of workload.
NOTE: I do NOT speak for or represent Amazon in any fashion. This is a customer to customer forum.
Disclaimer: I have examined any sites I provide links for and have determined them to be safe but I make no promises about safety, content, ads served or anything that might make you clutch your pearls in horror. Use discretion clicking on links provided by total strangers such as myself.