I recently watched an interview with a representative of Binance and he said that good projects that have the potential they can add to their exchange for free.
Yes, he said that. But Binance has the strict criteria to choose a "potential" and "good" project. I think these projects have to have an active team and a strong community behind.
Of course, the project must be really good and the team dev must have a clean history. In 1000 projects, only a few projects meet their standards. It is difficult to be listed in binance