If you are interested to compare emojis across platforms, I recommend going to emojipedia.org/ and see their platforms list at the bottom.
Some links:
Want to lookup emojis by category or search for emojis based on text? Use one of these.
This list is not curated, so I cannot guarantee the quality of these.
As far as I can tell, those all produce unicode emojis which you can copy and paste across platforms.
See projects on GH relating to #Emoji.
See /emojis endpoint on the REST API. Lists all emojis as PNGs e.g. 1f4af.png?v8
