Good list Anthony for designers, wish there was one for engravers.
It's like Rodney Dangerfield said "They don't get no respect"
As far as placing the artists names, French stamps (also Monaco & whatever else printed by Atelier du Timbre, Paris) followed no set rule.
This one was designed & engraved by Pierre Gandon based on an old tapestry and he placed his name on lower left in the design.
The Monaco one has the engraver J. Pheulpin again lower left and the painter of the original on the right.
Whereas Austria, Denmark, Sweden, Poland, Germany etc. always followed the rule; engravers name horizontally in the lower right border (never inside the design) and designer LL.
The only exception is where the designer & engraver are one and the same such as the one below from Hans Ranzoni d.J (the younger) who almost always worked solo.
Same as your 1937 blue French stamp, Jules Piel, he designed & engraved the stamp. He also worked on banknotes as did many other stamp engravers.