Every trig value you'll ever need lives here
The unit circle is a circle with radius 1 centered at the origin. Every point on it has coordinates (cos θ, sin θ) where θ is the angle from the positive x-axis. This single diagram encodes all six trig functions at every angle. Instead of memorizing isolated values, learn the unit circle and you have everything. The key angles: 0°, 30°, 45°, 60°, 90° and their equivalents in radians: 0, π/6, π/4, π/3, π/2.