Is there nothing? Great, go ahead and fill the void.
Is there so much that it becomes overwhelming to even look? If so, ask yourself: does your thing have any significant differentiators? Are you willing to maintain it? Do you want the people who come after you to see one more option in the sea, or an existing project made better thanks to your changes?
It's about respecting the time of one another. If I'm looking for a to-do app, I'm looking for a good one, at least in the ways that matter to me. Not for thousands of applications with the same exact issues. And so are you. Nobody needs a million of options that suck. We all want a handful or ideally one that does the job.