In Japan, its common to purchase pencils specifically for test taking. This is because not only do they need to be HB [for the OCR machines to be able to read the answers], some schools also require the pencils to have no words or diagrams printed on them.
Here are some test taking pencils I purchased recently.
Product name HiLINE Orenpitsu HB Pencils, Test Pencil Set of 3 Part Number PA002-540 size Pencil - H160mm, 4g / Cap H45×D12mm, 2g specification Three HB pencils with erasers and hexagonal shafts, plain body, exam-prepared design, with three break-resistant, connectable caps Manufacturer Kutsuwa Co., Ltd.
Features:
Break-resistant pencil
Long-lasting lead
Less likely to stain paper
Smooth writing
Eraser at one end
Break-resistant & connectable caps
In addition to the "usable" features, these pencils also come in lucky colors like gold, silver and metallic red. They are also have 5 sides [pentagon] making them less easy to roll away. In Japanese this is 五角 [Gokkaku]. This also sounds like 合格[Gokaku] which means to pass(exams) in Japanese.
Is this something common where you are from?
Would you try them?