It depends, if you purchase a single asset, you’ll only get that one. But if you purchase the whole bundle, it will include all assets, even the ones you already own.
Note: There is a special discount available for Mega Bundle owners when upgrading to the All-in-One pack. With the All-in-One, you’ll have access to all my assets with no need for future purchases. Please note that music packs are not included, as they are part of a partnership and not my own work.