Norway's national centre for Nynorsk teaching — free materials and writing guidance.
Details
The national resource centre for Nynorsk instruction, publishing free teaching materials, reading lists, writing guidance and exercises for the written standard that most courses ignore. If you need to write Nynorsk rather than just read it, this is the most substantial free collection available. Free and publicly funded. The important caveat is audience: it is built for Norwegian schoolteachers, so material is in Norwegian and organised by school year rather than by CEFR level.