Embrace that 3rd Party Universe :) Comment with your best links. I will try to update this and maybe some day we can make this a sticky.
https://edtools.cc/ all around a very good site with good tools for bounty hunting, trading, mining
https://edmining.com/ complete infos about mining. Builds, places, tips
https://inara.cz/ you should know this! link it to your accoutn and enjoy one of the best sites about elite
https://edsy.org/ tinker with ship builds. you can choose, ships, modules, blueprints and see exact values and changes
Currently still in development but I am working on my own client: https://github.com/arne-fuchs/edcas-client
I also started to work on a website where want to have functions like in eddb.io
I know there also exist edpn but it is just a personal project.