Here is a set of models I used for my Red Hood cosplay, based specifically on the animated version of Red Hood from Batman: Under the Red Hood. This collection includes the silver armor plates for his boots and gloves, as well as several pieces for his belt. I imagine they could be re-purposed for various other characters as well.
I printed these without support material and just sanded the bottom corners smooth.
The belt pieces are designed to snugly slide over those standard airsoft style combat belts, which usually go for $10 or so on Amazon. I just slid them over the belt and put the belt's actual buckle behind my back. To attach the boot "buckles" or plates, I used velcro, and to attach the glove armor, I used contact cement, like barge or weldwood.
Disclaimer: These were made for my costume and may not work exactly for you.