I have heard about sites like that which helps you check if your data has been leaked online.. I can't remember it's name though.. fact is trying to be more careful might endanger you even more. Those sites as well will require you share personal information with them for them to be able to carry out the search.. so what use will it be?

The best way to avoid having your data sold or leaked on the dark Web is being conscious of places you visit online. We visit a lot of website daily while browsing our phone. Some might be intentional, while some might be clicked because of certain ads that suddenly pops out on our screen.. we just have to be careful...