I wonder that there is not one place where necessary (?) third party add-ons, sources and knowledge is put into one place. I’m a newbie and my OT will arrive soon so I think it is for other beginners a good source as well. I make a start
If something missing here… share your knowledge please
OctaEdit
A paid cross-platform OSX/Windows software editor and librarian for the Elektron Octatrack DPS-1
Unfortunately not compatible with the latest update as far as I understand. http://octaedit.com/
Hard/Softcore
A single cycle waveform tool
Monolith
Turns your Elektron Octatrack into a multi-oscillator modular monophonic synthesizer based on wavetable synthesis http://project1404.com/monolith2/