The most commonly used arch is a Single Line Arch. Most arches are made using latex balloons. Another common arch is a Double-Bubble Single Line Arch.
Many examples of these are shown in the gallery.
Although rarely requested, it is possible to make a Single Line Arch out of foil balloons, or even out of transparent plastic Bubbles.
Link-balloon Arches are similar to Single Line Arches but are made using balloons which are tied end-to-end with each other.
Link-balloon Flower Arches are a more complicated construction, made using balloons which are tied end-to-end with each other.
Foil-Chain Arches are made using special foil balloons, giving a giant floating chain effect!
Spiral Arches have the same construction as Spiral Columns and are often used in conjunction with them.
A Champagne Bottle Arch is an interesting version of the Spiral Arch. One of these can really set the scene at a reception.