They often go by the name Sea container or c container. multiple sized available standard, half, quarter...
the was a company making them into "tiny houses" Inheard a pitch for a guy who wanted to make rent a gyms in them for small firms... you can always cut yourself a man door/windows with a plasma cutter...
back around 2007 or so there was a surplus of them due to a trade imbalance.. the ports couldnt find room to stack them all.
