Zen Coding/Emmet. Plugins that add its features exist for many text editors and IDEs.

The idea is simple: You write a very short CSS-path-like statement, and then press Tab (or whatever makes sense for the editor you’re using) to have it expand to a full HTML tree. It feels really nice to just type table.mytable>thead+(th*4)>tbody>tr>(td*4) and have it expand to

<table class="mytable">
  <thead></thead>
  <th></th>
  <th></th>
  <th></th>
  <th></th>
  <tbody>
    <tr>
      <td></td>
      <td></td>
      <td></td>
      <td></td>
    </tr>
  </tbody>
</table>

Or, if you are using HAML

%table.mytable
  %thead
  %th
  %th
  %th
  %th
  %tbody
    %tr
      %td
      %td
      %td
      %td

et cetera!

This has saved so much time .

IdeaVIM for the JetBrains IDEs.

emacs org-mode. I’m learning more and more…

I usually use Sublime, but I use Atom for Elixir. The atom-elixir plugin is very good!