Welcome! Many people are using a raspberry pi with SmartThings in many different ways.
It’s often the basis for integrations like smartthings to Lutron or smartthings to light wave RF. You’ll find a lot of the project reports on those in the project section. You can use the quick browse list in the community – created wiki and look at lighting projects, I think most of them are there. And there are a couple of different device type handlers on the dth list under miscellaneous.
You can also ask questions in the developers section of the forum as there are many different ways of making the connection.