pip install emoji_extractor
Usage examples: see this Jupyter notebook
It counts the emoji in a string, returning the emoji and their counts. That's it! It should properly detect and count all current multi-part emoji.
possible_emoji.pkl is a pickled set of possible emoji, used to check for their presence in a string with a few additional characters like the exciting VARIATION-SELECTOR-16 and the individual characters which make up flag sequences.
big_regex.pkl is a pickled compiled regular expression. It's just 2784 regular expressions piped together in order of decreasing length. This is important to make sure that you can count multi-codepoint sequences like '💁🏽\u200d♂️' and so on.
If you want to do stuff more complicated than simply detecting, extracting and counting emoji then you might find this Python package useful.
It may be possible to speed up the extraction/counting process by limited the regular expression used to only those which are possible, given the unique detected characters. I guess it would depend on how quickly the new smaller regex can be compiled. Storing them might be possible but the combinations are likely to be prohibitive.
Feel free to email me about any of this stuff.