According to the Logos wiki page, there is a logo for many components of OSM. There is a logo for the wiki, editors, conferences, communities, regions, etc.
The notes feature should have its logo because there are several applications for notes, people working on notes, etc. I proposed this logo, and I would like your opinions: Talk:Logos - OpenStreetMap Wiki
If there are not disagreements, I will include the notes logo in the page.