Paint Brushes, Spray Paint, Paint Rollers, Roller Extension, Masking Tape, Markers, Paint Tray, Primer, Bucket of Water and a Ladder. Most of the equipment is similar to the equipment required for Indoor Wall paintings. But while travelling or hunting for a good spot to paint in, it helps to travel light by carrying Stainers (concentrated shades of colour) and an emulsion base (to mix the Stainer into, for making the actual paint), along with disposable paper plates and plastic containers to hold water and mix paint in.
Different types of paints can make a drastic different to the nature of the artwork. For exterior murals - Exterior emulsion paints, 100% acrylic paints or enamel based paints are preferred as the walls you are working on will be exposed to all sorts of weather conditions. Work out a quick budget and buy the paints accordingly. Applying these paints is entirely up to the artist. It can be sprayed or applied by brushes and rollers. For a really gigantic sized mural a paint sprayer machine can also be rented.
Cleaning solvents, Fixer Sprays, Newspapers, Rags and Tissues.
Depending on the artwork you might need primer for a base coat followed by exterior emulsions etc. Don't forget to carry a pen knife or screw driver to prise open the cans of paint!
Different varieties of spray cans are priced differently. Work out a budget before you can decide what you need to buy. Spray or Aerosol cans are convenient for filling larger portions of the artwork and while working with stencils & cut-outs.
After choosing a spot to work in, set up a working area where all the material - paints, dishes, water and references can be laid out. It is easier to carry a single light base colour, and many small bottles of coloured Stainers which on mixing produce the exact colours, in the required quantity.