Blitz:GadTools

GadTools is an updated system of gadgets that was introduced in OS 2.0, and is supported in all versions from 2.0 on. It offers some large improvements over the standard Intuition gadgets and is the standard, familiar look from OS 2.0 to 3.1. It is quite low level meaning, and it lacks some more advanced features from the more modern toolkits such as MUI, but has a very low footprint and doesn't need any external toolkits installed to work.