Many open-access journals charge authors a fee to publish. This finds the ones that do not: journals in your field that are free to read and free to publish in, so cost is never the reason you cannot share your work.
The journals marked as no-fee are indexed in DOAJ and charge no author fee. That combination is often called a diamond open-access journal. DOAJ indexing is a real quality signal.
It is still a signal, not a guarantee of fit or standing. Check the scope matches your work, and run anything unfamiliar through a predatory-journal check before you submit.
Runs in your browser against the public OpenAlex index. Nothing is stored.