Replace those plastic pens with pens made from cornstarch. While plastic pen bodies are made from fossil fuels and just end up in landfill for decades/centuries, cornstarch pen bodies are made from sustainable plant materials and are biodegradable in compost environments at the end of their lives.
Mechanical pencils provide a long-life solution for regular pencil users. Just replace the leads as you use them.
Use Cornstarch Mechanical pencils and save the oil that goes into making plastic, and have the satisfaction of knowing that it's made from a biodegradable material.