Copy/Paste custom nodes

I created a custom node for OpenAI Assistents API and would like to re-use it.
How can we re-use nodes we created maually or with AI?
Can we make our own templates? How can I re-use custom nodes? I tried copy pasting, but it is not working.

At the moment I have to recreate every custom node multiple times to use it (or spending AI credits to create same node twice), which kinda defeats the purpose...