A list of Windows builds recently leaked. Builds leaked this year are shown here.
List:
Windows 8
6.1.7746.fbl_grfx.100428-2024
6.2.7880.fbl_grfx_dev1.101110-1700
6.2.7962.fbl_srv_wdacxml.110311-1930
6.2.7963.winmain.101113-1721
6.2.7989.winmain.110421-1825 (x86 chk)
6.2.7997.fbl_dnt3_wireless.110504-2014
6.2.8008.fbl_dnt3_wireless.110518-1900
6.2.8014.fbl_grfx_dev1.110525-1700
6.2.8045.fbl_grfx_dev1.110713-1730
6.2.8056.fbl_dnt2_bus.110727-1700
6.2.8056.fbl_dnt3_wireless.110727-1800
6.2.8140.winmain.111020-1857
6.2.8330.fbl_woa.120424-2227
6.2.8330.fbl_grfx_dev1.120425-1400
6.2.8330.fbl_ie_longhorn.120425-2121
6.2.8441.winmain.120623-1614
6.2.8513.win8_gdr_soc_intel.120710-2000
6.2.8513.win8_gdr_soc_nv.120710-2000
6.2.8513.win8_gdr_soc_ti.120710-2000
6.2.8518.win8_gdr_soc_nv.120718-0003
6.2.8520.fbl_eeap.120722-1632
6.2.8140.winmain.111020-1857