Sublime Text is free-ish, and you can open a whole folder in it and then do a normal find and replace or regular expression based. Doesn't support named groups for regular expressions though.

Free-ish, as in, it has an unlimited test period, but it will pop up from time to time when saving and asking you to buy a license if you like it. Similar to WinRar.

I can highly recommend it as a general text editor by the way. If you want to take a look, there are thousands of great plugins and themes available for it. Check out Package Control.