Tracks for the Pz III / IV were produced in many variations (7 main + multiple sub-variants and to ‘special’ tracks) throughout World War 2. Production time-frames of different designs overlapped heavily and were also different for individual factories.

Due to tack of spare-parts and limited production capacities all types of tracks were in use til the end of war, even though many track links were not usable with each other.

• Early tank variants (Pz III Ausf. A – G; Pz IV Ausf. A – E; StuG III Ausf. A) used small road-wheels and used a 36 cm wide track (38 cm with track-pins). They did not use the later (wider) variants. track-link; ‘Schneegreifer’(snow grousers / grippers, early type)

All later variants of tanks used the wider 38 cm (40 cm with track pins) track links. They were 6 different types (+ subvariants) plus 2 ‘special’ tracks (‘Winterketten’ and ‘Ostketten’).

• The early type 38 cm tracks were pretty much widened 36 cm ones (track-link). They could also mount the previous mentioned early type ‘Schneegreifer’, but can also be fitted with ‘Mittelstollen’ (Ice cleats). (Fitted).
• The step in development was the addition 2 ‘holes’ at the outside of the track-links to ease the addition of accessories. The remaining 5 main track types belong into this category. The differences are ‘relatively’ small. The Tracklink could be fitted with ‘Mittelstollen’ like the previous 38 cm variant but could be additionally fitted with ‘Hammerstollen’ (Teeth). The new ‘holes’ allowed a new design of ‘Schneegreifer’.
• The extreme weather conditions of the eastern front forced Germany into the development of ‘Winterketten’ (winter tracks). They were based on the previous 38 cm designs and were seasonal tracks (were put in storage in summer). The wide was 55 cm and the welded addition was ripped of quite frequently. They first saw action in winter 42/43. The track-links were asymmetrical (left/right) and could be fitted with the same accessories as the original track. Fitted with ‘Schneegreifer’
• The second ‘special’ track were the ‘Ostketten’. Other than the Winterketten, they were not seasonal, but regional tracks, designed for the eastern front. Designed for all seasons, the tracks were far more robust. The wide was 56 cm and the design was also asymmetrical. Production started in May 1944 and only parts of the tanks on the eastern front ever received those tracks. Like the ‘Winterketten’ the ‘Ostketten’ could also be fitted with previous accessories. Track-link.

Further, more detailed information to all German WW2 tracks, can be found in the German book ‘Panzerketten – Die Gleisketten der Deutschen Kettenfahrzeuge des Zweiten Weltkriegs’ by Dr. Peter Schwarzmann. Additional pictures and maybe infos (Russian? language) could be found here and here (German language).

Rough outline of German Panzer III / IV tracks and accessories [Reddit]