For my side-project, I'm using React for the frontend, Nodejs for the backend, MongoDB for the database.
Zoho for emails (great for side-projects that are not going anywhere :) )
Twitter, IndieHackers, Reddit to promote my product
What is your stack?
My blog -- jekyll hosted on Gitlab Pages
https://holidayapi.com -- php, nginx, mongodb for persistent storage, redis for both persistent and temporary storage / caching.
https://ginpop.com -- php, nginx, mysql for persistent storage, redis for temporary storage, memcached for caching in front of mysql
Outside of my blog, I host on Linode and utilize S3 for backups and for UGC storage. Gitlab + their runners for version control and CI/CD. EmailOctopus for marketing emails.
New stuff I have in the works will most likely be on a similar stack as you, Node.js, React, MongoDB as well as Redis for any caching / temporary storage needs.
https://trackmylift.app
ReactJS frontend, PHP backend, Firebase Auth, PostgreSQL database.
https://sheetcapture.com
NodeJS backend, serving frontend through HTML/Handlebars template engine