For target ammo, literally any brass cased FMJ factory ammo. For target ammo you want to spend a lot less than your self defense ammo.
Cheaper ammo means you can buy more, the more you buy, the more you practice, the more you practice the better shot you'll be when your life depends on it.
For target ammo I usually spend around $160 - 190 per 1000 rounds.
Blazer Brass, Winchester Whitebox, Federal American Eagle, Aguila, and Fiocchi are all suitable for target ammo.