We've been building sites using Drupal since version 4.7 (version 9 is now under active development). Over that time we've tried to find ways to contribute to the community that has created, developed, supported and promoted the platform we've used to make our living. We've provided support where we could, we've donated to the Drupal Association, but we haven't contributed code back to the community until recently.
Over several years we've built a couple modules that were created to solve specific problems with client requests. And in doing so, we've been able to pass those features on to other clients with similar needs and to provide the modules for others to download and use.
Now, these aren't major modules like Views or Media. But they are small packages of reusable code that make developing certain kinds of sites easier. And it's gratifying to see that other Drupal site builders have been able to take advantage of those developments.
These modules may seem arcane and bewildering if you are are not a developer, but if you're looking for tools already built to accomplish narrow tasks, you're welcome.
But we also contribute to the ongoing development of the platform by being a Drupal Association Member which requires an annual membership. It's well worth it!