You can also trawl through the Heroclix range. They are bigger figures so they don't look great with shorter figures like Hasslefree or copplestone, but fit just fine with Zombicide and Warlord Project Z figures. You can find anything from unarmed civis (mostly super hero alter egos) lightly armed civis mostly with pistols and a number of cops from beat walkers to riot gear.
They're not as easy to come by as they were in their heyday, but I know Troll & Toad still sells the singles for decent prices