There were only two generations of this truck line, despite the fact that it ran for 22 years. There were many interesting variations on the base model, especially on the GMC's. The Sonoma GT was a limited edition model sold in 1992. It had a L35 V6 engine, a big upgrade over the base I4. In 1991, there was a special edition called the GMC Syclone, which was technically sold as its own model line. It was a super truck designed for the sports truck segment.
Although not an official limited edition, there were some 1993 Sonomas that were shipped from the factory with a L35 W code engine. There was no way to differentiate these trucks from their less robust counterparts.
The special editions were dropped in 1994 as GMC introduced the second generation.
Although these compact trucks came from the factory with relatively weak engines, they shared the same G platform with many other Chevys, which made them a favorite for engine swaps. It is not uncommon to find one of these trucks with a Chevy small block making 400 horsepower or more. Some daring owners have even managed to put a big block engine in these trucks. Obviously, that makes them very popular with hot rodders.
You can find plenty of these trucks on the used market, especially on auction sites like eBay. They are heavily discounted compared to new prices, selling for about a third or fourth of the price of a new Chevy or GMC truck.