Looking for advanced project ideas?
(These are just some ideas I think are more complicated but might not be so complicated for you.)

• Create something with pen
  This could be a platformer or a piece of art
  

• Create a fractal
  Fractals are in a way, A special shape because when you zoom in, It will be the same shape all the time.
  You can use pen to create fractals.
  

• Make a game using only 1 script and 1 sprite
  Games like these seem to be pretty tough to create. 1 script and 1 sprite games seem to be tough to create because you need to create
  clones and variables all in one block of code and all in 1 sprite
  

• Make particle effects using pen
  Particle effects using pen are really interesting and look awesome! You can create cool effects like flames and smoke.
  

• Recreate a song using the music blocks
  You can choose your favorite songs to make using the music blocks. You can make music like: “Moonlight sonata” and “ode to joy”
  

• Make a cloud game
  You can use cloud variables to create a multiplayer game! Though, Sometimes the cloud servers for scratch go down from time to time.
  

• Make a 3D game
  You can use pen to create 3D mazes and more! There are many tutorials on how to make 3D games.
  

Questions

Q. How do I get the pen block or music block?

A. What you do is, Open a project then on the bottom left corner there is a blue button that has a symbol that shows 2 code blocks and a plus sign,
Click it, It will then ask you to choose an extension go ahead and click on the extension of choice. If you want to exit it , The button is on the top left corner.

Q. How can I create projects like these?

A. For example, If you are trying to make something like a pen platformer. You can search for a tutorial on how to create one.
Also if you want to learn more about cloud variables and pen go check out @mathmathmath 's tutorials on how!
(Cloud: https://scratch.mit.edu/studios/3951281/) (Pen: https://scratch.mit.edu/studios/4136128/)