Basecamp is a popular low-friction project management tool. Their “boosts” are very much like this.
Mastodon “boosts” are their version of a simple retweet, or Tumblr’s reblog. I felt for a moment that using this term could be confusing – but the intent is obvious as soon as you use it.
It does have that sound. I don’t know what else I’d name it, but if it’s rolled in as a kind of enhanced reaction I suppose it wouldn’t need a name at all.