-NPCs DMG-
Angel - All (explosive-kin)
Amarr Navy - EM/Thermal
Blood - EM/Thermal
Caldary navy - Kinetic/Thermal
Gallente - Kinetic/Thermal
Guristas - Kin/Therm
Khanid - EM/Thermal
Mercenary - EM/Thermal/Kin
Mordus - Kinetic/Thermal
Sansha - EM/Thermal
Serpentis - Kinetic/Thermal
Zazzmatazz - All

-DMG to NPCs-
Guristas = Kinetic
Angel = Explosive
Serpentis = Thermal/Kinetic
Thukker Tribe = Thermal
Ammatar = Thermal
Blood Raider = EM
Sansha\xb4s = EM
Khanid Kingdom = EM
Rogue Drones = EM
Republic Fleet = Thermal
Mercenaries = Thermal/Kinetic
Mordus = Kinetic

Stacking penalties: with 10% base bonus
1 100% 10 %
2 87% 8.7%
3 57% 5.7%
4 28% 2.8%
5 10.5% 1.05%
6 3% 0.3%

https://wiki.eveonline.com/en/wiki/DED_Complex_List