I've marked request for Wikipedia in Basaa [1] as eligible. It's a Niger-Congo language spoken in Cameroon [2], spoken by 300,000 people [3]; valid ISO 639-3 code.
[1] https://meta.wikimedia.org/wiki/Requests_for_new_languages/Wikipedia_Basaa [2] https://en.wikipedia.org/wiki/Basaa_language [3] https://www.ethnologue.com/language/bas