1. Clone Stamp Tool - it's useful in removing watermark from the other photos. Really, how silly I am. Plus, the Eyedropper Tool = "OK IT'S MY WORK!". But I don't encourage doing this, we should respect and give credit to the original creator.
2. Pen Tool- This is my favorite cutting tool, I mean, extracting/removing a certain image on a background. This is the best tool because you can control its curves.