I hear you. I am almost up to 18k bookmarks. Not bragging either. Classification becomes increasingly difficult. However, I can rcmd a couple/few helpful plug-ins...
Mainstay:
[Use Chrome Extensions (or similar add-ons/apps in alternative browsers)]
0.) Search Bookmarks (Enables searching your bookmarks from Omnibox; type b-m-space in your omni and then term(s)/keyword(s) for the bookmark(s) you are searching for... they will appear in the suggestion drop-down... or, press return to search bookmarks using Chrome Bookmark Search, which will match the term(s) you've entered): https://chrome.google.com/webstore/detail/search-bookmarks/m...