Whether you’re a casual streamer or a YouTube superstar, Keymailer makes it easy for content creators to request and receive keys for Steam games to showcase on their channels.
After you sign up they are some requirements .
REQUIREMENTS
Have at least 50 subscribers to your channel on YouTube or 50 followers of your channel on Twitch.
Tag at least 3 pieces of recent Twitch or YouTube content using the official tags - these can be found on a game's page on Keymailer.
You have to complete those requirements to receive keys to your email directly from the publishers . https://www.keymailer.co/
