This site offers clipart designed for classroom, including books, pencils, etc. They charge an annual license fee.
ClipArt Etc offers over 71000 clipart illustrations designed to be appropriate for classroom use.
Clipart.com has hundreds of writing-related cllipart images and stock photos. They charge a subscription fee.
Clker offers free clip art that is shared by different users and sources.
Draw a Pencil Videos
You can also learn to draw your own pencil. There are many videos on YouTube that will show you how.
Graphics Factory has over 800 images tags under writing. The site charges a membership fee.
iClipart for Schools
iClipart has a special site for schools that contains school, reading and writing images. They charge a subscription fee.
iStock charges per image and offers clipart and photos. Images include typing, books, typewriters, writing illustrations and more.
MyCuteGraphics offers cute original clip art that includes pencils, books, reading and more.
Shutterstock is best known for carrying photos but they also have a big clipart section that you can search for writing-related clipart.