As noted, A320-100s were just the first couple of production frames in 1988, and all went to either Air France (some via Air Inter, whom they bought a few years after delivery) or British Airways (they were originally ordered by British Caledonian, but BA bought them out prior to delivery). None of them are still in operation.
Very quickly the Wingfences were added (the winglet things to increase fuel efficiency), and this standard version became the -200 (and remains so to this day).
When Airbus launched the A321 (first delivery in 1993) and A319 (first delivery in 1995), the baseline -100 versions already included the Wingfence. Air Canada operate the -200 version of the A321, which has an increased max take off weight over the 321-100 series (ie heavier duty landing gear/suspension), as well as provision for extra Fuel Tanks (these are optional). The A319 is only available as a -100.