There are multiple ways to make use of frottage (rubbings) to create art, that involve the inclusion of natural forms, outdoor elements, urban scenes, still lives, typography and lettering, and other abstract/experimental techniques. Frottage was significant in surrealism as it allowed for spontaneous and unexpected imagery.

I know it's a long post, but there's so much overlap I didn't want to split it across multiple posts and make people go back and forth to find materials lists and such.

You will need:

Textures:

• natural - leaves, flowers, shells, bark, etc.
• outdoor - sand, sidewalk, raised/depressed lettering, brick work, etc.
• surfaces - fabrics, rough paper, textured objects, etc.
• unconventional materials - sandpaper, lace, grids, grillwork, Lego, etc.
• objects with varying shapes and sizes
• textures

Drawing/painting materials:

• soft graphite pencils
• crayons
• pastels
• coloured pencils
• charcoal
• watercolours
• gouache
• acrylics
• ink

Other:

• paper
• roller or brayer
• brushes
• blunt drawing/embossing tool

Tips:

• Make sure the paper you use isn't too thick or you won't be able to capture texture through it.
• Hold the drawing tool at an angle and gently rub it across the paper to best allow for the texture or relief of the textured surface to transfer.

How:

• Choose texture/surface.
• Place paper over desired spot.
• Use your chosen drawing material to rub over the spot.

You could:

• Choose a natural and/or outdoor textured surface. Try - leaves, bark, gravel, ground layer, branches, flowers, etc.
• Choose cityscape images or objects representing urban scenes. Consider specific architectural elements - statuary, facades, windows, doorways, decorative elements, historical sites, and street textures.
• Use different sizes and types of papers to to capture what you want.
• Make composite scenes by incorporating different perspectives/views into a single piece.
• Consider using one dominant colour for the entire piece.
• Use the textures of weathered/decaying urban elements and combine those with the use of worn or distressed materials.
• Create a texture map by documenting the textures of different urban areas or neighbourhoods.
• Find surfaces with lettering/logos - buildings with embossed letters, textured walls, raised patterns.
• Capture different lettering styles, sizes, surfaces, letter forms, words, font styles, calligraphy, alphabets of different languages, phrases, historical buildings or monuments with inscriptions.
• Integrate typography into textured backgrounds.
• Enhance portraits, landscapes, etc. by incorporating quotes, signatures, or typographic elements.
• Overlap objects to create different compositions and texture combination.
• Create transition frottage that moves from one object to another.
• Combine different techniques, tools, surface materials, ink washes, paint splattering, dripping, masking, blending colours, layering textures, shading, various pressure intensities to create different effects.
• Combine embossing with frottage by using a blunt tool to press into the paper to capture depressions and textures.
• Use frottage to emphasise negative space by highlighting the areas around the textures rather than (just) the textures themselves.
• Combine frottage with unconventional mark-making tools such as found objects, unconventional brushes, or natural tools to create abstract textures.
• Experiment with chemically treating the paper before/after to alter textures/create unexpected effects.
• Use completed pieces as collage elements or the surface for another work.
• Combine various creative techniques to augment results - stencilling, etching, linocut, mixed media, etc.
• Alter the textures of materials by crumpling, folding, or distressing them before using them for frottage.
• Use as a way to map/document textures found in various environments.