If you play KeyForge, you know the pain of tracking what cards have armor and how much of it is used up each turn. Age of Ascension, the latest set, only made this a ton worse. (My spouse has a deck with three Abond the Armorsmiths. Three.)
I put together little double-sided shield tokens that you can use to keep track of armor. Start them on the full side to show how much a creature has, and flip them over to the cracked side as they absorb damage. Then flip them back at the end of the turn.
I have the SVGs for the armor tokens as well as other things on the KeyForge Accessories section of my website, but you can also right-click and download the SVG here:
To make them, you do one engrave and the cut around the outside, then flip the rectangle over and drop it back in its hole. Then you engrave the other side and do the cuts for the tokens themselves. It’s a bit fiddly, so I went and made a YouTube video that shows how to do it.