I've found Allan Oliver's document on 1937 Coronation covers very helpful in organising my own small collection
As Allan comments: " The information I have been able to find on these covers is very limited and as far as I am aware, no list has been made of the various different types that exist. This booklet is intended to make a start on remedying the latter" and ,as far as I know, his document originates from 2004.
In his document Allan lists those countries where he knows a particular cover type was produced.
In my own collection, I've found additional countries not detailed by Allan.
I've also found other cover types not mentioned by Allan.
Largely for my own interest, I've produced a companion document to Allan's detailing additional country covers and detailing different cover types. I've included scans of such covers and also added any other information I've been able to glean.
In case it's of interest to anyone else the list itself can be accessed as a pdf file:https://drive.google.com/file/d/1pB...Gt5Zct-/view
I've also put together a spreadsheet file that tabulates each individual cover type with the countries known to have issued it:https://drive.google.com/file/d/1Y7...W9YTvYc/view
There are now over 160 individual cover types identified and over 400 covers across the Commonwealth countries.***Links Fixed By Mod***