There are many sizes of balloons to choose from:
'260' is a balloon that is 2' diameter and 60' long when fully inflated. It is often used for one-balloon animals, such as the basic dog, giraffe, or poodle. Most of the standard sculptures are geared towards the use of '260' balloons but the 160 or 350 sizes can also be used.
'350' balloons are 3' in diameter and 50' long when fully inflated. They make nice fat animals and are visual for stage shows.
'160' balloons are 1' in diameter and 60' long when fully inflated. They can be used with those with small hands, or just to make any sculpture cuter and tinier.
'321' or bee body balloons can usually be easily inflated by mouth. They can be used for bee bodies, apples, pumpkins (or any stemmed fruit), jumping mice, etc.
'Blossom' (or 'Geo') balloons and 'Heart' balloons are uniquely shaped balloons that great in balloon bouquets. Add to the center of a balloon bouquet, or use as an accent in your unique balloon sculpture.
'Round' balloons with patterns imprinted are a great finishing touch to your balloon sculpture, or add extra kick to your needle through balloon routine.
Latex gloves can be used to sculpt hilarious balloon characters.
Markers: both 'marks-a-lot' and 'sharpie' are good, as they have a lower alcohol content than most other markers.