aviket

This Plugin searches all the posts, pages with a blog. You have to enclose the term you want to search 
with shortcode like [findwordsc]Searchterm[/findwordsc]. The plugin “Searchterm” is searched throughout the blog. A rolling carousel is displayed 
which contains button links to all the posts and pages, containing the word “Searchterm”. 
After clicking the link, the post is displayed in a modal popup(Thickbox). In the post thus displayed by clicking on the link, all the occurrences of search 
terms are highlighted. The highlighting style is controlled by settings. 
The settings page is opened by clicking in the “Findwords options” menu item in the settings menu. 
mark.js Javascript/ Jquery plugin is used for highlighting. 
Link to the mark.js plugin: 
https://markjs.io

Findwords

This Plugin searches all the posts, pages with a blog. You have to enclose the term you want to search

Marios Alexandrou

This plugin allows you to dynamically (i.e. at the time when a page is generated) replace code and text from themes and other plugins with code and text of your choosing before a page is delivered to a user’s browser.
Because the find and replace happens in real-time no changes are needed to plugins or themes which means upgrades remain easy!
A <a href="https://infolific.com/technology/software-worth-using/real-time-find-and-replace-for-wordpress/#pro-version" rel="nofollow ugc">pro version</a> (a lifetime license is less than $15) with additional filtering options, setting export/import functionality, and the ability to modify admin pages is available.
Here are some common uses:
<ol>
<li>Want to selectively translate text that is being output by another plugin? You can do that.</li>
<li>Trying to tweak the text on a product or shopping cart page? No problem.</li>
<li>Hoping to remove footer text from a theme without modifying the theme? That’s easy.</li>
</ol>
Here are some <a href="https://infolific.com/technology/internet/handiest-wordpress-plugin-youve-never-heard-of/" rel="nofollow ugc">more examples</a>.
And some <a href="https://infolific.com/technology/internet/wordpress-seo-with-real-time-find-and-replace-plugin/" rel="nofollow ugc">tips for those interested in on-page SEO</a>.
Remember, all of the above can be done WITHOUT modifying themes or plugin files so you’ll always be able to upgrade them without having to worry about losing custom edits.

Real-Time Find and Replace


Works realtime and can parse regex



Handy note:use / or ~ start AND end, use \1 \2 etc to replace with the ( ) groups


Works as advertised

Set up find and replace rules that are executed AFTER a page is generated by WordPress, but BEFORE it is sent to a user's browser.

Findwords vs Real-Time Find and Replace