Stuff I find useful. You may also. Or not.
I still occasionally use SNR (Search 'N Replace) by Thomas Lundin but it no longer seems to be available for download. This is A Pity.
An alternative might be Funduc Search & Replace for Windows. I don't use it myself, but I do use Funduc's Directory Toolkit. Funduc's feature-rich software is kept up to date and has been very reliable.
A venerable tool, SED, the stream editor is well-documented here.