Dplug is a plugin wrapping framework inspired by WDL.
I used it to make two plugins already:
https://www.auburnsounds.com/products/Panagement.html
https://www.auburnsounds.com/products/Graillon.html
The goal is to have a rather easy API to use with minimal hassle. Though it does lack in features a bit.
Dplug manages rendering a bit to have graphics that are procedural with a touch of realistic lighting. This system can be bypassed if you don't like it. The goal of it is primarily to reduce file size and avoid 3D models.
For example this plugin release is about 4.5mb (32-bit and 64-bit, VST and AU for Windows + OSX).
You can find a comparison vs WDL on Github:
https://github.com/AuburnSounds/dplug
Price is free with a bounty system to support bug fixes and enhancements.