Amazon Lightsail is described as 'The fast and simple VPS hosting service from Amazon, the easy way to launch a virtual private server. You can have a VPS up and running with just a few clicks' and is an app in the online services category. There are more than 50 alternatives to Amazon Lightsail for a variety of platforms, including Web-based, Linux, SaaS, Windows and Mac apps. The best Amazon Lightsail alternative is DigitalOcean. It's not free, so if you're looking for a free alternative, you could try Ubicloud or Stacktape. Other great apps like Amazon Lightsail are Heroku, Linode, Microsoft Azure and Hetzner.
Similar prices but cheaper once you deploy something bigger, proper IPv6 support in all regions while Lightsail only supports IPv4 at the moment, more regions, more OS choices and a faster an more easy to use API.