Self-hosting, the concept in which you host your own applications and data. When self-hosting, you know exactly how your data is managed and stored. While it does add extra complexity in comparison to many cloud services, self-hosting is the way to go if you want to be in control and you value your privacy. For example, all you need to set up Google Drive is a Google Account. Nextcloud is a self-hosted alternative to cloud storage and does require you to install and manage it.
Here you will find guides on all kinds of self-hosted software. Some are related to Home Assistant and others might not be. I do try my best to integrate all my self-hosted software with Home Assistant and if possible, I will detail how I achieved that.