Text Tools: Google Sheets Add-on
A free Google Sheets add-on for bulk text editing across thousands of cells

What it is
Text Tools is a free Google Sheets add-on that lets you edit text across thousands of cells at once. Insert text before or after values, add prefixes and suffixes, and preview changes before applying them.
What I did
I built and published it on the Google Workspace Marketplace, where it has about 118 installs. It started as a companion to Instant Currency, aimed at people who spend a lot of time cleaning up spreadsheet data by hand.
How it works
You select a range, open the sidebar, type what you want to add (a prefix, suffix, or text insertion), and preview the result before committing. It works on large selections without slowing down. The most common use case is things like adding area codes to phone numbers, appending domains to company names, or wrapping values in formatting.