EwinRacing offers an esports sponsorship program for gamers and streamers. They get a large number of sponsorship requests and aren't always able to provide support to everyone. Every sponsorship request will receive a timely response.
Apply here: https://www.ewinracing.com/content/27-sponsorship
If you're afraid you won't be brought on as a sponsor, they also have an affiliate program.
Becoming an EwinRacing affiliate – means working side by side with a passionate team of gaming industry professionals all over the world, promoting best in class gaming chairs that change the way gamers play the game, cooperating with top eSports teams, and being a part of the video game development community. Gamers from North America to Europe love and value the EwinRacing brand and you can help grow this community.
Benefits of the program:
Apply here: https://www.ewinracing.com/content/28-affiliate