Today, I watched a video from a Tryton event in 2013 in Barcelona, Tryton from a User-Perspective - Axel Braun - YouTube. They were talking about a wiki, and about end-user documentation in general. I don’t really see anything like that, but would like to make something. I am not sure how big the user base of Tryton is, but guess that everything that lowers the barrier of entry, should help, in particular in the face of all these new web-based accounting packages that are springing up as SaaS offerings, potentially strangling smaller players like Tryton. Also, there is no mailing list, correct?
Thinks have changed a lot since 2013 
We used to have a wiki and mailing list but then we moved back to discourse and everything is now part of discourse. The main usage of the wiki was to discuss new developments and we have now a Feature category to have such discussions.
We also have a How to category which several tutorials on how to do some process with Tryton.
Also our documentation have been improved on last years, specially to some work related to the GSOD project.
Having said that I must admit there is so much work to do and we will appreciate to have more hands helping to improve the documentation and including more tutorials to the forum.