zabatonni

Automatically finds duplicate terms (with same name) in each taxonomy, then moves posts from duplicates to its original terms and deletes duplicate terms.
You can choose which duplicates you want to merge and delete.

Merge duplicate terms

Plugin for easy merging duplicate terms (tags, categories, ...)

Daryll Doyle

This plugin merges ACF tabs across field groups into a single tab list.
Very useful if you’re re-using field groups across templates and don’t want all your tabs to display seperately.
Requires <a href="https://www.advancedcustomfields.com" rel="nofollow ugc">Advanced Custom Fields</a> to work.
N.B. This has only been tested on ACF5 so may not work on the 4.x versions. 
See <a href="https://en-gb.wordpress.org/plugins/acf-merge-group-tabs/" rel="nofollow ugc">this plugin</a> if you’re using older versions of ACF.

ACF Tab Merge

This plugin merges ACF tabs across field groups into a single tab list.

Merge duplicate terms vs ACF Tab Merge