drafting instrument - tools used by draftsman to make high precision markings and technical drawings

proportional divider - looks somewhat a compass, used for equally dividing segments, also allows for scaling of measurements so they can be transferred

protractor - tool shaped in a half circle, and almost always transparent, used to measure angles or circles

triangle - also known as a set square, often used in conjunction with a protractor or compass, the triangle is used to draw 90 degree angles

T-square - Two straight edge pieces which intersect at one end, used to draw straight measured lines. Older T-squares were made of wood, whereas more modern ones tend to have clear plastic edges.