Hello everyone!
Here in Scandinavia there is a real resurgence of traditional paint finishes.
Oldest is 'slamfärg' in swedish. Red oxide earth pigment boiled with
water, vitriol, linseed oil, and oats, I believe. Can be purchased readymade, but it is popular for folk to make their own.
https://youtu.be/ksa_lHcEutU
Linseed oil paint is the other. I love that stuff. Interior and exterior.
https://youtu.be/zFeq61pg_3o
The most popular manufacturer over here is ottossons. They have a great instructional YouTube channel, also in English.
https://youtu.be/AEUsMf-4m_Y
Hope this helps.