A simple plastic holder designed for four six-sided dice. Comes with a second holder for your opponent, and a small breakaway support holding them together. (Single holder can be found here.
When it comes to tracking life points in card games like Magic, most people like their d20s or their special dial counters, but I've never been able to get past the simple utility of using four d6s. They're easy to see from a distance and from any angle, you can always add more if your total goes past 24, and they're about as compact as it gets as far as cramming things into your deckbox.
To that end, I've thrown together a simple holder to make this method a bit easier. It's mildly aesthetically pleasing, perhaps, but mostly it just holds the dice together while making it quick and easy to pull a die out as your life points dwindle to nothing and your opponent laughs maniacally.
Side note: I carefully sized these to be a perfect fit for the plain dice I had lying around, which are just regular Yahtzee dice. These dice are a little variable, and so is the 3d printing process, so there might be some adjustments involved.