Other than Facebook are there any social media that helps in self-promotion?
I've found Twitter and Instagram are pretty good
I agree with Sev R. While Instagram ISN'T good for promoting individual videos (lack of the ability to make easily linkable links) you can always do the old trick of sharing the thumbnail, then put "link in bio" as the description. However, unlike Twitter, if you use hashtags on Instagram for your thumbnails, it gets a bit spammy and you might not get the results you hoped for. I find behind the scenes of future videos is a better way of using Instagram.
Twitter I'd probably say is the best "dumping ground" for self promotion. Those who follow you for that reason, generally know what they've signed up for. But some may be more interested in a conversation rather than a promotion.
Thank about it this way, when you're watching your favourite free to air television show, do you REALLY enjoy watching the promotions, or are you there to just watch the movie? Some promotions (letterbox junkmail) is super annoying, so you want to be providing some value (or passion) in any reguard. "me me me me" is obvious and people see through it.