If you currently use TextEdit or another basic text editor to write your code, I like Xcode. In HTML, it color codes everything and indents lines to make it more organized.
Even though this isn't related to web development, I also like Memory Clean, which removes unneeded file cache from the RAM when space runs low to make your Mac faster. Be careful though, as sometimes it can actually make it worse. There have been times where the cleaning actually uses RAM and makes the computer freeze.
If you have a lot of items in your menubar, I like Bartender (I have the free trial and changed the trial start date to extend the trial). Normally, as you install apps, they put icons in the menubar and it eventually becomes cluttered. Bartender (good pun, right?) tends to your menubar and allows you to move items around, hide them, and put them in a separate bar for easier access.