1990 saw the first distinct boots and shoes appearing on figures, which make them look much more realistic, as long as they're not day-glo pink or purple or some other stupid colour, and the start of the Pirates theme which has been going strong ever since. I still have some pirates I bought new at the time. Probably 95% of my figures post date 1989, and I prefer the older ones for realism.
For me the 3666 Castle from 1993 was the peak of the Knights theme, when it was still recognised that a castle could not function with knights and nobles alone, you needed some workers too. The modern castle fails in that respect, and also isn't so nice to look at. 1993 saw a massive release of new sets in the knights theme, most of which are still greatly sought after by people who missed them at the time,
1994 saw the first Specials, and guess what, I have several of the original specials too. I only regret that after the first dozen specials I stopped collecting Playmobil for several years. This coincided with my buying a house and starting a new job, so I probably had too many demands on my time and finances to keep track.