Kuáti.fi: Learning materials for early childhood education of Saami language and culture, maintained by the Finnish Saami Parliament. Materials are available in North Saami, Inari Saami and Skolt Saami.
Giellagáldu: The common language planning body of Saami languages.
Oahpa! Grammar, learning tools etc. for many Saami languages.
I just found a great etymology-based database for Saami (and other Uralic) languages, including proto-languages and less common languages like Akkala Saami, Ume Saami, Nganasan, Mator, Ludic (Lydian), etc: Álgu at the Kotimaisten Kielten Keskus - Institute for Languages of Finland It takes data from a wide variety of sources, so orthography and reliability are inconsistent. But for some of the lesser-known languages it's one of the best databases I've seen so far.