I looked around for another product like this and couldn't find anything else. I took a bit of a risk on this as I wasn't able to find the table of contents to see if the battles would work for me. I've got to say I'm really, really impressed. The battles are all really interesting with great tactics for the monsters/NPCs, and can function as quests that you can drop into an existing campaign (you could also string them together as a series of shorter adventures and build a campaign out of it). I'm playing an adventure path that takes place in a large city and wanted to have lots of options for the players to take.

What if they want to rob a powerful wizard? (there's a series of battles where there's a mad wizard who just died and left behind some cool loot with lots of traps/constructs defending it)
What if they are approached by a gang of theives? (there's a battle for that - the PCs have to avoid blackmail by infiltrating another theives den) What about if they want to fight some epic monster? (there's a series battle leading to a very memorable encounter with a dragon) Storm and hold a castle against an orc hold?

With a bit of creativity I was able to instantly give my PCs plot hooks into 5 of the series of battles at the start of the campaign. It gave them a ton of options and made what was a fairly linear adventure path into a total sandbox.

The quality of the encounters is really great, and the 13th ago icon system works really well in pretty much any system. I'm using it on a D&D adventure path running using the dungeonworld ruleset.

I can't recommend this highly enough.