Instruments other than the guitar that use effects that are traditionally reserved for the guitar, like fuzz, guitar amps, volume and wah pedal. If you want to use bass guitar as examples that's fine also.
The bass intro to Black Sabbath "NIB" sounds like a bass guitar through wah pedal
The Beatles "Savoy Truffle" which is one heavily distorted production features a wall of sax sound heavily distorted or fuzzed.
King Crimson "21st Century Schizoid Man", I think also has distorted sax, fuzz bass and vocals
The Beatles would put pianos and harmoniums through their Vox guitar amps "Penny Lane" especially the feedback at the end is from a piano through a guitar amp and "Birthday with tremolo effects
John Cale would put guitar strings on his viola and you hear it on songs like "Venus In Furs" or the screeching sound that you hear on "Heroin"