I kill ... I wound ... I will make mine arrows drunk with blood, and my sword shall devour flesh. Deuteronomy 32:39-42
After God kills off the old soldiers in his early retirement program (29) and before the new, youthful army begins to kill again for him, he brags a bit about some of his past killings. He is especially proud of knocking off an entire race of giants, the Zamzummim.
That also was accounted a land of giants: giants dwelt therein in old time; and the Ammonites call them Zamzummims; A people great, and many, and tall, as the Anakims; but the LORD destroyed them. Deuteronomy 2:20-21
There were a few other groups that God also killed that I don't think I've accounted for yet: the Horim, Avim, and the Caphtorim.
As he did to the children of Esau, which dwelt in Seir, when he destroyed the Horims from before them; and they succeeded them, and dwelt in their stead even unto this day: And the Avims which dwelt in Hazerim, even unto Azzah, the Caphtorims, which came forth out of Caphtor, destroyed them, and dwelt in their stead. 2:22-23
The Bible doesn't say how many were in these groups. So I'll just guess 5,000 for the lot of them.