Well if you don't know the guy in your picture is a Future Wars survivor from Copplestone castings.
http://www.copplestonecastings.co.uk/
They're a bit short but can work.
Maelstorm's Edge makes a great set called the broken
https://www.maelstromsedge.com/medge/store.jsp
Interestingly the hands are open, so they don't need to carry weapons.
From
GW, Catachans make great factory workers, Flagellants slaves or prisoners, and Brettonian Men At Arms (now
OOP) robed citizens.
WWX has tons of steam punk figures but I don't know how well they scale with
GW.
https://www.wildwestexodus.com/
Reaper has some steampunk in both metal and bones.
http://www.reapermini.com/OnlineStore/steampunk
Oh and this article is a bit old but I'm rather proud of it...
https://www.dakkadakka.com/wiki/en/Civilian_Life_in_Warhammer_40%2C000_AD