Nikolay Bachiyski

In WordPress you can set individual templates for pages, which allows you to easily include additional functionality. Unfortunately this feature is not available for posts. Here is where this plugin comes.
After installtion you will be able to choose a template for each post the same way you do with pages.
You can find <a href="https://codex.wordpress.org/Pages#Creating_Your_Own_Page_Templates" rel="nofollow ugc">how to your own templates</a> in the Codex.

Templates for Posts

The same as page templates, but for posts.

MMDeveloper

A wordpress plugin that lets you search for text within your templates.
Built by The Marketing Mix Perth: https://www.marketingmix.com.au

Search My Theme

I had to fix an issue of broken image paths on a website that I had not developed. The other developers were using an ip-based image path, which broke when the site's IP changed. This plugin let me search for the IP and find where it was being referenced to in the files. It also let me search for a CSS selector. Fantastic plugin, will probably use again!

Templates for Posts vs Search My Theme