The internet is terrible for cocktail recipes. Discovery is terrible, recipes are badly listed most of the time, and the blogs don't curate well.
Youtube is not that bad if you can find a good channel with someone that has actually worked in a bar, but even then, they tend to go downhill after a while. It's a time limited gig.
The best way to grow your repertoire is to go to Goodwill and browse the book section there. The dollar bin section at any bookseller is good too. Used bookstores too. I have no idea why this is, but these crummy non-seller books have the best recipes and the best curation; it's bonkers. Sure, grab Smugglers Cove and the other hits, actually read them. But I have found that the best cocktail recipes are in the books no one wants anymore.