According to various sources, about 6000 Albanian civilians disappeared during the Kosovo War. Most of them were found and were identified, and about 1600 are still missing. The Batajnica mass graves
is the largest with 744 dead. Many of these bodies came from the Meja massacre, where 300 refugees were executed, including 36 children. The Rudnica mass grave is largest one in southern Serbia. What initially looked like 250 bodies turned out to be remains of 52 civilians. That mass grave was covered by a parking lot. Then, another 61 Albanian bodies were found in Petrovo Selo in eastern Serbia, 84 in Lake Perucac, eastern Serbia, and 9 in Krizevak Quarry, southern Serbia. But there are also mass graves in Kosovo: Bellacerka 77, Dragodan cemetery 170, Pastasel 106, Brusnik 28, Rahovec 47, Bishtazin 80 and North Mitrovica 76. All of the above are known sites with mass graves of civilians murdered by Serbian troops.

Reference

https://www.hlc-kosovo.org/storage/app/media/Zines_Varrezat%20Masive/mass_graves_eng.pdf