There are many alternatives to Movie Renamer for Mac and since it's discontinued a lot of people are looking for a replacement. The best Mac alternative is FileBot. It's not free, so if you're looking for a free alternative, you could try TVRenamer or mnamer. If that doesn't suit you, our users have ranked eight alternatives to Movie Renamer and three of them are available for Mac so hopefully you can find a suitable replacement.
TVRenamer is a Java GUI utility to rename TV episodes from TV listings. Basically, it will take an ugly filename like Lost.S06E05.DD51.720p.WEB-DL.AVC-FUSiON.mkv and rename it to Lost [6x05] Lighthouse.mkv.
mnamer (media renamer) is an intelligent and highly configurable media organization utility. It parses media filenames for metadata, searches the web to fill in the blanks, and then renames and moves them.