Hello,
Recently, I asked for contributing help on social media.
The following story resulted from that:
Some months ago @nextcloud asked for contribution, e.g., by translating #Nextcloud: Nextcloud 📱☁️💻: "Ready to make a difference? 🌟 Join Nextcloud’s #O…" - Mastodon
Since then, I’ve added for Brazilian Portuguese about 2000 missing translations and reviewed more than 25000 existing translations, changing and correcting many mistakes and inconsistencies.
At the moment, Nextcloud is fully translated for pt_BR, including user documentation. 
So my hero of the day is @fbausch 
Transifex: fbausch_t
Mastodon: @fbausch@chaos.social
P.S: My selection for the postings is a subjective choice on my part. If someone wants or should be mentioned here > please contact me.