I enjoy watching others do tricks on Trial bikes (with the low saddles). What is the best type of Handlebar for this type of bicycle?
Standard MTB handlebars will work for trials. My recommendation would be an aluminium bar with a 31.8mm or 35mm clamp area. With the 31.8mm bars you will have quite a few options on stem length and angle. 35mm bars will have less options as the are really geared towards downhill. The rise of the bars is purely rider preference.