Not sure if this is helpful, but for myself, it was essentially a post on ProductHunt & emailing some journalists.

The ProductHunt post was augmented by the fact the product (https://uimovement.com) was clearly for a certain community (designers), so it was picked up and shared on other publications/social media accounts within the community.

From the PH post, it was picked up and shared on DesignerNews, r/web_design, Webdesignernews, Codrops, Smashing Mag, etc. The other sources brought in way more traffic than PH in the end.

For more long-term, but slower growth, automating social media has been helpful too, but that can only work for content-heavy products.