I got a set of nodes with a gradient, and the emission shader output. I would like those cubes to be more reflective almost like glass, and to be able to control their transparency if possible. How do I set up the nodes to the emission shader?
Because Emission turns your mesh into a light, and it doesn't deal with normal surface responses, you can use an Add Shader here to add the emission effect to a Glass BSDF.
The rest is down to your lighting setup.
You can decrease Emission a little to get some translucency.