Resetting tags to default

Your options in order of time investment:

1. Get that com.apple.finder.plist back from a Time Machine backup that occurred before you removed the tags.
   1. Run /Applications/Time Machine.app
   2. On the first Finder Window of that interface, press shift+cmd+G to open a Go To Folder panel
      1. Copy and paste: ~/Library/Preferences into that interface and press return.
      2. In that new Finder window, use its search field to enter: name:finder
   3. On the Time Machine interface, retreat in time to before you removed the tags, and from [2.2], click on the com.apple.finder.plist file and then click Restore.
   4. Reboot, and then check Finder > Preferences > Tags and review if the basic tags have been restored.
2. Boot into Recovery and reinstall the operating system (as suggested by BDAqua).

And if you mean you went into Finder Preferences : Tags, and whacked everything, then that's another issue. If true, launch the Terminal and enter the following:

defaults read com.apple.Finder FavoriteTagNames

You should see:

and if nothing appears, you will need to get the Finder plist back from your preceding Time Machine backup by using /Applications/Time Machine.app. The file in question to restore is:

/Users/yourname/Library/Preferences/com.apple.finder.plist

Beginning with Monterey, Apple stopped storing the custom Finder tag names in a local .plist and began preserving them in a sqlite3 database. I have an AppleScript that can get the original tag names and append a list of custom tag names from that database to produce a sorted list of known tag names. These are not automatically entered back into Finder preferences though.

If you mean in the Finder Sidebar, make sure they're checked in Finder > Preferences > Tags.

Which tags?

Ah, there it is, never saw down that far before, thanks!:)

You're welcome. They are pretty far down. 😎

I suspect reinstalling the OS would bring them back.