What are some good tags you can put on your YouTube videos if you upload BO2 trolling Borderlands 2 Gameplay

The best thing to do here is to see what tags the top ranked videos have used for your keywords.

Youtube stopped making these publicly available on their site since late 2012 but you can use a neat FREE software tool called "Youtube Tag Extractor". You can download the tag extractor from the related link. Then just enter the URL of the top ranked Borderlands 2 Youtube video and it will extract the tags that were used for that video.