Modules are the objects that perform the visualization itself: they use data to create the visual elements on the scene.
Here is a list of the Mayavi modules along with a brief description.
Axes: Draws simple axes. ContourGridPlane: A contour grid plane module. This module lets one take a slice of input grid data and view contours of the data. CustomGridPlane: A custom grid plane with a lot more flexibility than GridPlane module. Glyph: Displays different types of glyphs oriented and colored as per scalar or vector data at the input points. GridPlane: A simple grid plane module. HyperStreamline: A module that integrates through a tensor field to generate a hyperstreamline. The integration is along the maximum eigenvector and the cross section of the hyperstreamline is defined by the two other eigenvectors. Thus the shape of the hyperstreamline is “tube-like”, with the cross section being elliptical. Hyperstreamlines are used to visualize tensor fields. ImageActor: A simple module to view image data efficiently. ImagePlaneWidget: A simple module to view image data along a cut. IsoSurface: A module that allows the user to make contours of input volumetric data. Labels: Allows a user to label the current dataset or the current actor of the active module. OrientationAxes: Creates small axes on the side that indicates the position of the co-ordinate axes and thereby marks the orientation of the scene. Requires VTK-4.5 and above. Outline: A module that draws an outline for the given data. ScalarCutPlane: Takes a cut plane of any input data set along an implicit plane and plots the data with optional contouring and scalar warping. SliceUnstructuredGrid: This module takes a slice of the unstructured grid data and shows the cells that intersect or touch the slice. Streamline: Allows the user to draw streamlines for given vector data. This supports various types of seed objects (line, sphere, plane and point seeds). It also allows the user to draw ribbons or tubes and further supports different types of interactive modes of calculating the streamlines. StructuredGridOutline: Draws a grid-conforming outline for structured grids. Surface: Draws a surface for any input dataset with optional contouring. TensorGlyph: Displays tensor glyphs oriented and colored as per scalar or vector data at the input points. Text: This module allows the user to place text on the screen. VectorCutPlane: Takes an arbitrary slice of the input data along an implicit cut plane and places glyphs according to the vector field data. The glyphs may be colored using either the vector magnitude or the scalar attributes. Vectors: Displays different types of glyphs oriented and colored as per vector data at the input points. This is merely a convenience module that is entirely based on the Glyph module. Volume: The Volume module visualizes scalar fields using volumetric visualization techniques. WarpVectorCutPlane: Takes an arbitrary slice of the input data using an implicit cut plane and warps it according to the vector field data. The scalars are displayed on the warped surface as colors.