The three main types of scaffolds are:

1. Supported scaffolding - consists of platforms supported by rigid supports such as poles or frames from the ground up. It is modular and versatile, commonly used on most building sites.
2. Suspended scaffolding - platforms are suspended by ropes or cables from an overhead structure, ideal for working at heights where ground-supported scaffolds are impractical.
3. Aerial scaffolding - scaffolding mounted on aerial lifts or platforms that can be raised and moved as needed for access to different heights.

These categories cover various specific scaffold designs for different construction needs.