I am a fan of Google Drawing. While it does not have all of the features of Adobe Illustrator, I am able to create quite a bit with it. What I especially like about Google Draw is that it is collaborative and the drawings are in my Google Drive with the rest of my documents.
Unfortunately, Google Docs, Sheets or Slides do not allow for inserting a Google Drawing. You are able to insert->drawing and create a new drawing, but you are not able to simply access your Google Drive and insert the drawings you already have.
The inserted image can be resized if needed.