At https://community.snowdrift.coop we put a lot of thought into reactions[1], specifically about how they promote healthy interaction. There are a few in particular I'd like to highlight:

# "Changed my mind" (icon: graduation cap)

In most communities, this is a overload of the upvote. But it's a particularly good kind of upvote, the complement of the usual echo-chamber "upvoting because I already agree". The icon+phrasing combo reframes "I lost the debate" into a positive thing, more like "I was educated". It's my far my favorite reaction to receive -- lots of warm fuzzies. In order to avoid confusion/misuse, we did not make this the primary upvote (that's thumbs up, with the verb "appreciate").

# Sympathies (icon: blue ribbon)

It's a bit tasteless to "like" or "heart" sad news (eg, someone passed away). At the same time, a downvote isn't appropriate, either. This fills the role of "support for the person posting, not the topic they're posting about".

[1]: You can see some of it, as well as the full set, here: https://community.snowdrift.coop/t/custom-emojis-esp-as-reto...