Outbound Link Checker is a very simple tool to use. You simply enter your websites domain and it will crawl every page looking for outbound links. Once it has an outbound link it will check for any reason you might not want to be linking to this website. For example has it being hacked and its serving up Malware? Has it being deindexed by Google?
Google is smart and when you consider how much money they invest in maintaining quality search results do you think they're going to want to server up your website when you're linking to a hacked website hosting malware or linking to a website they've just deinxeded because its part of a PBN. Have you checked all those webstes you're linking with to see if they've expired and being turned into a spammy PBN? Probably not, because thats a massive task. But with Outbound Link Checker it takes about 3 seconds to start the you just let it run and investigate anything it flags up.