I searched for a list of computer graphics techniques on the internet and couldn't find such a list. So I prepared one. Here is a list of techniques that I think are important. It's a high-level description. For example, you won't find something like "screen space ambient occlusion" in this list.
Graphics Techniques (2D)
Drawing 2D Primitives
Pixel and Point
Line
Rectangle
Polygon
Circle
Ellipse
Curve
Text
Image
Fractal
Transformations
Viewing
Clipping 2D primitives
Alpha
Transparency
Compositing
Filling
Stroking
Antialiasing
Gamma Correction
Transitions
Tiling
Sprites
Layering
Scrolling
Particle Effects
Collision detection
Graphics Techniques (3D )
(For Real Time Rendering)
Rasterization vs Raytracing
3D Graphics Pipeline and different coordinate spaces
3D geometric primitives
3D representations
Modeling Transformations (Scaling, Rotation, Translation),
Viewing, Projection and Cameras
Viewports
Clipping
Making use of GPU resources and synchronizing CPU-GPU communications
Shaders: Vertex, Pixel, Tessellation, Geometry and Compute
Texturing
Lighting, Colors, Materials and Shading
Shadows
Reflection
Transparency and Translucency
Antialiasing
Gamma Correction
Curves, Curved Surfaces and Tessellation
Depth Testing
Blending
Stenciling
Scissoring
Collision detection
Picking
Particle Effects
Special Effects
Animations
Spatial Data Structures and Rendering optimizations
Realtime Raytracing
