Here are a few more:
-Most antivirus apps - especially Norton, Avira, Avast, and almost all available on the App Store
-Adobe Flash and Acrobat Reader
-Oracle Java
-All third-party browser toolbars and search extensions
-Some online backup software like Carbonite
More to come...
C
I was a late comer getting on the computer/internet bandwagon. In 2009, my quandary over Mac v. PC was resolved by the ubiquitous bus stop ad campaign showcasing the sexy and slender MacBook Air. I was the hapless naive user who thought it was way cool that I stumbled upon this app that would "clean all the clutter on my mac" and I would watch as a hammer goes up and down while a wrench turns a bolt (gifted people such as myself are able to discern the technical meaning of this). Pretty soon, never-before-seen toolbars would magically replace my normal browser interface. Baby, I was on a roll! One day, Satan saw my glee and so persuaded God to render my hard drive useless. I reproached God for taking counsel from Satan, whom he surely knew was corrupt and malicious. God, feeling a little silly for having not vetted his top advisor more carefully, was a little embarrassed and i found myself with the mid 2013 MacBook Air which is greatly improved over the earlier version, as was its user.
Sorry for that long paragraph, but aside from the satirical Biblical overlay, it's an accurate description of my experience. Jumping now to the present, when I was looking at the version of this page that had advertising (before I registered), directly below your post was none other than a promo slot for MacKeeper replete with the same ridiculous Michelin-Tire-looking superhero mascot. Presently, MacKeeper and CleanMyMac promotion appear all over the web including websites one might assume would have high ethical standards for advertising. It may be naive of me, but if I were working in public relations for Apple I would expose these menaces in a big way as the fraud that they actually are.
A little less clear to me, and by extension probably to many others, is the importance of removing Adobe Flash and Acrobat, and Oracle Java - simply because so much content on the internet won't work unless you're running them.