First there was a box and then there were some strings, and then we had a guitar. In essence, a very simple affair. Complicated perhaps by use of flatpicks or finger picks, or perhaps a bottle neck or piece of metallic tubing to act as a slide. But not much more than that. Come the electronic age and the arrival of the pickup and amplifier and the whole game changed.
Guitar amplifiers with a simple pickup just allowed the sound to be heard by more people. However, boys will be boys and special effects started to be introduced in the amplifier. Dating back to the early sixties, you can hear the reverb on a lot of early pop music. The true menace of reverb though, was first exploited by artists like Link Wray.
As the sixties progressed, sound distortion started to arrive and you can hear a lot of this kind of effect from the late sixties onwards. It makes the tone of the guitar very fuzzy. As is often the case with many things from that period, it was used to excess. The technique is used much more variety and with more subtlety these days.
Guitar accessories go beyond those that affect or alter the sound of the instrument. Guitar cases for example, come in a wide variety of shapes and sizes, from modest gig bags to toughened flight cases to protect professional instruments when taken on aeroplanes.