Last year i have launched https://visalist.io which helps people find where they can travel with your passport tension free. Im currently making $2500 per month and it's going to cross $4000 hopefully. My revenue is from adsense, pro subscription, iVisa affiliate and Skyscanner affiliate. Most of traffic is organic. I stared visa list as i found contradicting, confusing and outdated information about visas. So i tried to solve my own problem and it turns out there more than 300k users with similar problem every month.