I started down this road several months ago, and decided to write my own system that can grow and change as I discover how I want to organize things. It's roughly modeled off of a traditional categorized card-catalog system, with the addition of zettelkasten-style numbered links. As a concrete example, here's a card that I added today:

  [[379]]  Sjö Milljarður Manneskjur
        |  Tölvuleikur - Forritun
        |  Inventory - Steam library
        |  Computer Science - Concepts - Multiprocessing
        |
        |  ,,Seven Billion Humans''
        |
        |  2018; re: concurrency
        |________
        |  Backreferences:
        |  [[380]]  Tomorrow Corporation
        |        >  2018: [[379]] Seven Billion Humans