QTM - QTM is a blogging client which is presently capable of composing, formatting and submitting blog...
Rss builder - RSS Builder is an easy to use program to create RSS news feeds and podcasts for your web site.
SeMagic - Client for LiveJournal, Blogger, Wordpress
Feed Launch .NET - Feed Launch .NET is an open-source feed editor for RSS 2.0 and ATOM 1.0 Feeds.
MarsEdit - MarsEdit is a desktop blog editing application for the Mac. It provides an offline interface to most popular blogging systems. WordPress, Blogger, Tumblr, Movable Type, and many other systems are supported.
Feeder by Reinvented Software - Feeder is for creating, editing and publishing RSS feeds on macOS.