I have just completed a table of all the events since the beginning of Gems of War including when each new troop/weapon was introduced: http://gems-of-war.wikia.com/wiki/Events
Please take a look and let me know if there are any errors.
I could use some help from the more veteran players (or devs if they’re reading this). There are two blanks near the top of the table where I couldn’t source which weapons were in the glory shop for the first two events. I’m also not sure if there was something in the glory shop prior to the first event I could find (Mechanical Mayhem).
Please feel free to post the answers here or add the information to the wiki yourself.