I’m selling deadcoins.com (cryptocurrencies) due to lack of time to continue work on its features. It has around 300 visitors per day and more importantly, a very decent backlink profile.
Keendly delivers articles from news aggregators straight to your Kindle so you can sit back and enjoy them like you would enjoy a book. Allows to schedule automatic deliveries every day and fetches full article content from webpage. Web application is a PWA (Progressive Web App) which allows you to install it on a mobile phone.
A bot that keeps Trello cards in sync. There's also https://teams.cardsync.xyz/, a version that works as a Trello Power-Up. It is tied to Trello teams (so all team members can use) instead of to a single Trello user -- it also uses custom bots per team instead of a single global bot.
FontGala.com is a 4 years old MyFonts affiliate site with 34,000 premium fonts. The site is fully automated and has steady growing traffic and sales. It made $1750 in the first 3 months of 2018.