Good news is anyone can do it, implementing additional video sites doesn't require any changes to the app like NewPipe - just requires any dev to write a plugin and share it online. Grayjay's plugin system is pretty well thought out IMO, there's a brief overview on YT covering how to develop one
Since Veoh also has a login system, that could make things take longer since a dev would now need to think about optional account integration features
It will either come to Grayjay when a community member makes the plugin to add it as a source or FUTO has enough interest from the community to create it themselves.