From memory:
The original ~87 Maguras had very chunky levers attached with a sort of jubilee clip and were popular on Monty trials bikes from the time. I think these are the ones Saracens shipped with in the early 90s. Monty experimented with all sorts of extended brake lever blades to improve leverage but the basic design stayed the same.
They changed to an all forged lever design for the HS-22 model which must've been around 92-93. These were grey or RaceLine fluro yellow but were identical internally AFAIK. They had 16mm cylinders in the levers. There was also a cheaper HS-11 with plastic lever blades.
Later they introduced the HS-22 RaceLine-D (D for downhill) - probably around 95-96 - with a reduced 14mm cylinder in the lever for increased leverage. At the same time they added a Jonny T model as Tomac was riding with Maguras at that time, in red and a very rare 'Trial' model in a sort of orange colour, both with 16mm lever cylinders. There was also a limited edition version in white with the 14mm cylinders and some funky red cnc lever blades.
After that, the slimmer HS-33 models came out in around 98, along with the cheaper plastic lever bladed HS-24. The HS-33s came in many colours over the years, including quicksilver, raceline yellow, Jonny T red, SID blue, snowwhite, green frog etc, and all used the smaller 14mm pistons. They must've sold at least a billion HS-33s to trials riders around the world by now. In the last few years (after I got bored with trials and Maguras and therefore lost my once encyclopaedic knowledge of Maguras ;-) they introduced the really slim line HS-33 lever, similar in design to their disc brake levers - with the master cylinder perpendicular to the handlebar.