And not like one drama, which I don't remember the name of, where the ML just had words/threats, to say, but ment nothing and protected no one. Like, he can protect the FL from powerful or rich men who has their eyes on her. 

  • Mr. Sunshine - The ML does attain some power through hard work and risking his life, but it is very precarious / could easily be lost at any moment.
  • The K2
  • Zhang Gong Zhu Zai Shang
  • I Hear Your Voice - ML doesn't have "power" power, but he does have the power to read other peoples' thoughts. He has enough money to get by on his own, but isn't rich.
  • Hometown Cha-Cha-Cha - More courage than smarts.
  • You Are My Glory - The ML does not have money or power and is very smart. So this drama meets those parts of your criteria. However, the FL was never really in physical danger in this drama. The ML "protects" her at times by coaching her and protecting her reputation. He shows courage at times in more mundane ways (e.g., through his life choices).
  • Queen In Hyun's Man - Possibly? I can't remember if / how the ML protected the FL but I'm pretty sure he did. As a time traveller, he had no money or power in the present.