Just in case you have to do a fresh re-install of InDesign (or your entire system)? Yeah — (that reminds me …)
* Plugins: no, except those you installed from third parties. (But these ought to be re-installable from their original medium. Of course it's anyones guess where their private settings are stored! You'd have to ask the supplier. Where are my high scores from Tetris stored?)
* Scripts: no (for the “Application scripts”) and yes (for all “User scripts”, which you may have written yourself, or downloaded and put in there). That's everything in the folder “(your name)/Library/Preferences/..” and then some, depending on your ID version, for Mac, and some entirely other place (too long to remember…) for Windows.
* Preferences: Yes!
* You forgot: Print and PDF Presets: Yes!
The first post here: https://forums.adobe.com/thread/526990 outlines the procedure for backing up your prefs and presets on both platforms.
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