Checkerboard:  Generates a checkerboard pattern. You can specify the checkerboard size and colors, and the sharpness of the pattern.

Circles:  Adds concentric circles to your image.

Grid:  Generates a grid with modifiable positioning, color, distance, and width.

Lenticular Halo: Simulates a lens flare. 

Random Generator: Generates an image of infinite extent whose pixel values are made up of four independent, uniformly-distributed random numbers in the 0 to 1 range.

Random Noise: Creates random noise with option for grayscale.

Render Clouds: Generates cloud-like noise, also known as Perlin-noise.

Star Shine: Generates a starburst pattern that is similar to a supernova; can be used to simulate a lens flare.

Stripes: Generates a stripe pattern. You can control the color of the stripes, the spacing, and the contrast.

Sunbeams: Generates a sun effect.

Sunburst: Generates a two color sunburst.

Linear Gradient: Generates a gradient that varies along a linear axis between two defined endpoints.

Radial Gradient: Generates a gradient that varies radially between two circles having the same center.

Circular Screen: Simulates a circular-shaped halftone screen.

CMYK Halftone: Creates a color, halftoned rendition of the source image, using cyan, magenta, yellow, and black inks over a white page.

Dot Screen: Simulates the dot patterns of a halftone screen.

Hatched Screen: Simulates the hatched pattern of a halftone screen.

Line Screen: Simulates the line pattern of a halftone screen.