Zenkit

Besides references and tasks, you can add many other media to your notebooks. 

To add files to your notes quickly and efficiently, type "/" and select "File Upload".

A new window will open from which you can choose where to upload your file. 

You can drag and drop the file into the upper field.

By clicking on "Select file", you can select files from your device.

If you want to add a file from an external storage location, choose Dropbox, Google Drive or Box.

They will be redirected to the corresponding page where they can log in and then select the file to upload.

"Enter a link" allows you to add a link to your page.

Select "Drawing", a canvas will open where you can draw anything you want.