The problem of identifying the casualties falls into several sections:
- which military units and which individuals were there?
- what relevant records were created at the time of the battle?
- where were those records kept, where were they archived and where are they now?
Which units took part and their commanders are included in most decriptions of the battle. Names of the common soldiers would be in the unit muster rolls.
There are unit histories and diaries and local chronicles which give contempory accounts. Only some of the officer casualities are mentioned in the chronicles I've seen. Muster rolls for each of the units would give names of the casualties even if rolls before and after the battle had to be compared. There were probably burial records created locally, as most of the bodies would not have been transported far.
Austrian military records are archived in Vienna. These can be accessed by researchers but are reputedly complicated because of the cataloging and sheer volume of records. Prussian records were in Potsdam and Berlin. Some of those records were destroyed in WW2. Not sure about access.
Church records in Silesia were archived in regional church archives, depending on denomination. Some were destroyed in WW2, some are in Polish church or regional archives, some were microfilmed before WW2. However, none of the villages near the battle site have microfilmed records from 1741.
Whatever has survived that might contain the names of the casualties (it would never have been a single list) would have to be accessed in person at several archives.
Familienkundlichen Literaturdatenbank references 2 periodical articles that are relevant:
Gefallene Helden der Schlacht von Mollwitz vor 200 Jahren im Kirchenbuch von Ohlau / Schircks, Eberhard, In: Familiengeschichtliche Blätter 39, 1941, Sp. 167-170 [translated title: Fallen Heroes of the Battle at Mollwitz, 200 years ago, [named] in the Church Register of Ohlau]
Auszug aus den Kirchenbüchern der evangelischen Kirche in Ohlau, In: Der Deutsche Herold 21, 1890, S. 110-111 [translated title: Excerpt from the Church Registers of the Lutheran Curch in Ohlau]
According to my Dad, there was a monument commemorating the battle, that was on, or visible from, the road between Mollwitz and Hermsdorf. It probably did not include a lot of names. I have searched for a historic postcard or current photo of that monument but haven't found any digital images of it. (I checked Google Streetview through Mollwitz, and the only monument in the village is the World War I cenotaph beside the church. Streetview does not include the road into Hermsdorf).
[This question has been bugging me because my paternal ancestors were in the near vicinity and the battle's outcome was pivotal to their lives].
I actually found a list of casualties of the Battle of Mollwitz in an archive, the Landeshauptarchiv Sachsen-Anhalt. As a part of a collection of military documents belonging to Leopold II, Prince of Anhalt-Dessau (“Verschiedene Militaria aus der Dienstzeit des Fürsten Leopold Maximilian im Königlich Preußischen Heer, 1733-1750”) it might be limited to participating troops from Anhalt. The signature is Z 44, A 9b IIIb Nr. 6 Bd. II.