Jorge I think you're getting lonely here being the only one posting new stuff.
I've searched all over the place looking for examples and couldn't find anything in my collection until I realized I forgot about my own country's stamps. Canada Post
has contracted out it's stamp production to various printers in the last 40+ years, therefore for various reasons the same definitives were sometimes printed by 2 or even 3 different printers.
There are sometimes differences in the paper or perforations but in other cases the only way to tell them apart is if you have an imprint block.
The following stamps were all printed multicolour lithography and except for minor colour differences they are indistinguishable.
The 43c Flag definitive first appeared Dec 1992, sheet & booklet printed by Ashton-Potter Limited
Subsequently APL went bankrupt and in January 1994 Canada Post
replaced them with Leigh - Mardon Pty. Limited a printer from Australia to assist Canada Post
's other security printer Canadian Bank Note who couldn't handle the volume of printing definitives and commemoratives and besides CP likes to have 2 printers available.
Ashton Potter reappeared around 1995 this time as Ashton Potter Canada
Limited but within a few years left Canada altogether and set up shop across the border in upstate New York as Ashton Potter USA
and now print a large portion of American stamps.
I don't have an imprint block for this one but here is a Leigh - Mardon single. They printed sheet & booklet stamps.
Leigh - Mardon didn't last long either and by November 1994 the old dependable Canadian Bank Note Co took over, again printing sheets & booklets.
It's virtually impossible to tell apart the APL stamps from the CBNC, same GT4 Coated Papers paper & same perf.
Leigh-Mardon stamps though have perf 14.5x14.6
while the other two are 13.6x13.1
Here are a couple of booklet stamps.
So here you have different printer varieties without much variety.