List of Essential and Useful Packages for the Atom Editor

whitespace
First on the list is whitespace, a core package that included with Atom.  It annoyingly removes whitespace at the end of documents.  Recommendation is to disable it.

wrap-guide
Another core package that is included with Atom. Displays a vertical line at the 80th character (column) in the editor. This is for when you want to see how the code would wrap in e.g. a console window that is 80 columns wide. IMHO this wrapping stuff is legacy and bullshit and should now be deprecated in favor of modern methods of displaying, wrapping text. So the recommendation here is to disable it.

hidpi
Essential if you are using a large display which is basically what most people are now doing in the modern world. The one setting that needs to be changed is Hidpi Scale Factor. Depending on the size and resolution of your display, this value may need to be higher or lower. Start with a value like 1.5 and work up or down. Every time the value is changed you have to resize the window to get it to take effect.

atom-beautify
It’s hard to imagine living without this useful package. It allows code to be beautified by pressing Ctrl-Alt-B. The default settings don’t always get things right. For example I’ve noticed it removing or adding spaces around CSS comments, causing them to be in the wrong locations. So double-check after you beautify just to make sure it’s working right.

Themes

Seti UI and syntax themes
I find the Seti UI and syntax themes to be the most appealing and so do many others based on the number of downloads.