Those would be emojis not emoticons.
Thanks. I never knew the distinction between the two. These emojis are usually used as reactions in our company to indicate you read a post, are investigating, giving kudos, etc. We actually have an entire document in Confluence specifying which ones to use, for which reactions.
You are absolutely correct about the ambiguity and problematic emojis. The trigger issue was the usage of hearts as "kudos" reactions. That's where we use the thumbs-up emojis now.
The idea of a reference webpage is a good one, but with Slack allowing you to upload your own emojis (and us using some -- such as the Piccard facepalm and "modern solutions" meme), we'd have to be very careful to show only the default ones.