What do you mean by "producer?"
People who make music? People who help people make music?
I am a maker of music and I help other people make music from time to time. All I need is a piano to make music. But I do have a fairly extensive collection of gear. I don't really have gear lust anymore. I went through a period where I was always craving the latest gadget ... in the end I realized that all you really need is the talent.
My lists ...
I apologize for any broken links in the above lists.