I started GatsbyTemplates in 2019, when Gatsbyjs was a shiny new tech everyone talked about. It was directory of templates, free, opensource and paid. In 2020 I was able to finally deliver first premium template. And less than in a month I've got a sale!
...but next 6 months was only crickets
So far I got very few sales, and decided to make some crucial changes:
- completely rewrite project from scratch with focus on technical SEO
- add templates from envato with affiliate links
And... IT WORKED!
From this point, I've sustainably got $50/mo. Then I added some more my own templates - that turned out not so effectively, only sometimes it increased revenue, but not so much.
For last year I abandoned the project while still collecting revenue and the only cost for me was domain renewal.
So, I decided to sell it on Flippa. Found interested buyer who got a new plan for this project. 
With gatsbytemplates I learned a lot. And only due to my actions project was worth something in the end.
Time to move on and create more!