Arches National Park has over 2000 arches within its boundaries. Many are on the maps and on designated trails, but many are unnamed and are found by accident when exploring the park.
The listed trails in Arches are busy ones and there are usually many people clustered around each of the highlighted arches. For these trails, go early in the morning (or in winter). Better yet, create your own route up the slickrock or across the sands and explore, finding unlisted arches and new viewpoints.