I usually don´t write that much about WordPress, but I´m currently helping out a business with their blog. Over time they have gathered a massive amount of comments. Sadly, about 99% of these where spam-comments. To make it a bit more sad, they have approved a lot of these comments as legit.
This of course gave me a huge headache as one of my job is to clean it up and move it over to WP Engine.
Luckily there´s a simple plugin that fixes this whole problem: Delete All Comments.
Under you can see the before and after image. Pretty snazzy I think.
Of course this is a pretty niche problems, but it´s really helpful when you actually need it.