A while ago I asked about a slack syntax exporter.  I cpy text from org to slack often enough that I spent an hour or two today writing a simple one, which I put up in a  gist:

If people are interested, I will be happy to package it up & put on melpa or whatever (would be the first time for me).

I mostly am interested in copy-paste, not in producing permanent files, so I use it with this simple utility function:

(defun ora-org-export-to-clipboard-as-slack ()
      "Export region to FMT, and copy to the kill ring for pasting into other programs."
      (interactive)
      (let* ((org-export-with-toc nil)
             (org-export-with-smart-quotes nil))
        (kill-new (org-export-as 'slack) ))
      )
    (global-set-key (kbd "C-c W s") 'ora-org-export-to-clipboard-as-slack)

The "ora" prefix reflects its origins in an old oremacs function that I use for (much more involved) HTML copy-paste:

- [[https://github.com/abo-abo/oremacs/commit/6c86696c0a1f66bf690e1a934683f85f04c6f34d#diff-ecff87135600df0cafffb47c303ae9c6][abo-abo's code from oremacs]]
- [[http://kitchingroup.cheme.cmu.edu/blog/2016/06/16/Copy-formatted-org-mode-text-from-Emacs-to-other-applications/#comment-2735698988][john's original post]]

SO far it seems OK. There are doubtless still bugs so probably it would be better to make a repo after all!