DEV keeps it simple with three reactions to posts:
- Like (aka Heart, ❤️)
- Unicorn (aka ??, 🦄)
- Reading List (aka Bookmark, 🔖)
These are tallied up as part of the "hotness" score that is used to promote articles on the dev.to feed.
Essentially making an "upvote" system where users can weight votes between 0 and 3 (and no "downvotes" or negative voting).
The only extra special reaction is that Bookmark/Reading List. Clicking that reaction adds the post to your personal reading list, saving posts you want to revisit for later.
(and comments are even simpler, only having the like (aka heart) reaction. The number of comments and their total likes also factors into that "hotness" score)