there are many Icinga Web 2 modules around. The Icinga project provides official modules and many community members have created their own modules too.
There's a compiled list of official and community modules here:
Icinga Exchange allows you to share your modules too (choose 'modules' as category on creation):
Or search on Github:
Watch Eric's introduction from Icinga Camp Berlin:
Carsten and myself did a talk on OSMC 2017 including Icinga Web 2 modules:
There also is a (German) training available here:
It is also worthwhile to look into the official modules and their code to learn best practices with the MVC framework and how hooks, controllers, views, etc do work in general.