Buypass Go SSL
Buypass Go SSL is an SSL certificate provider from Norway. They support the ACME protocol and have their own root certificate. The issued certificates are valid for 180 days. This is twice as long as the 90 days for Let's Encrypt and ZeroSSL. The ACME API URL is https://api.buypass.com/acme/directory and they don't require additional authentication, like an API key.
Pricing
Buypass Go SSL is a free service of Buypass.