Damaged Goods UK - 1990 / 1994
I am not sure how many exists with Iron Maiden imagery.
I have seen printruns from 1990, 1992, 1993 & 1994. The postcards varies slightly for each printrun, mostly on the back. I have these below and some of them more than once with slight variations.

Various variations of the backs

Dee Gee - 1995
I think that Dee Gee was in fact the same company as Damaged Goods. They might just have changed the name.
The catalog #'s for the lower numbered cards from Dee Gee, are identical to those of Damaged Goods. I have these below.

If you know of any other Iron Maiden postcards, or know something else about these please contact me.