In my new b2evo installation I need only "_core" and "sessions" modules, so I tried disabling all other modules in _application.php
Disabling "files" module:
Various errors in places where avatars are displayed, errors on post edit screen
Call to undefined function get_FileCache()
Disabling "collections" module:
Various blog-related errors in stats
Lots of blog-related related stuff still displayed like slugs tab, antispam, options on features tab, dashboard link.
For some reason tools controller is hidden along with custom plugin tabs :(
Disabling "sessions" module: kills b2evo completely
The only modules that do not trigger errors while disabled are "messaging" and "maintenance".