Is there any way to list the tags that are currently part of a given Tag Group? i.e. If I make a change to the Rate for a given Tag Group, which tags will I be affecting?
Assuming the Tag Group has a unique name you could use the Find/Replace tool to search all of your Tag Providers. You can then select all the results and copy/paste them into a text file.
Scripting can also achieve this, but I wouldn’t recommend it unless you will be repeating this process often.