Expression

Emojis such as the sobbing or skull emoji are iconic, but honestly can it really beat a good '(╥﹏╥)' or "(＠_＠)'. Now obviously that depends on the conversation and what tone you're going for, but they're super fun and there's a large variety of expressing that emotion. I find it hard to express what tone I'm going for through text, especially if I don't know them, so I overthink it and worry on how I'm supposed to type something to make it clear. Here's and example: 

OMG💀 = "damn that's crazy" or "uhmm.." energy

OMG ∑(O_O;) = "holy shit" energy

Like I said before, it 100% depends on the situation, but kaomojis change the mood entirely and are **OBJECTIVELY** cuter. The tone is more softer and playful, making it open to other people interacting with the message or just appreciating it. Also, emojis such as the skull and sobbing are giving that "nonchalant" energy, to which I think is kinda silly and boring. I swear, a ':sobs:' message is more expressive than 😭 and it isn't even a emote. 

Variety

There is SO MUCH you can do with a kaomoji, you've probably seen them it comment sections on other platforms as well, here are a few popular ones:

( ╯°□°)╯ ┻━━┻
( ´-ω･)︻┻┳══━一
／＞　 フ | 　_　_| ／` ミ＿xノ /　　　　 | /　 ヽ　　 ﾉ │　　|　|　| ／￣|　　 |　|　| (￣ヽ＿_ヽ_)__) ＼二) ∩――――∩ || ∧ ﾍ　 || || (* ´ ｰ`) ZZzz |ﾉ^⌒⌒づ`￣ ＼ (　ノ　　⌒ ヽ ＼ ＼　　||￣￣￣￣￣|| 　 ＼,ﾉ||

You don't even have to write a single sentence to express what you're trying to say, it's like a fun sticker ☆*:.｡.＼(≧▽≦)／.｡.:*☆

Where to find?

There are SOOO many websites that you could lose track, but my personal favorite is probably Kaomoji: Japanese Emoticons website because it has all of the basic kaomojis you can use and has a very cute interface (KONATA!!). If you want larger kaomojis, then go to emojicombos, although you'll have to type "_____ kaomoji" in order to find it. I discovered that there's a website to create kaomojis as well (snskeyboard), but I personally haven't done it yet so I can't say my thoughts regarding it. Thanks for reading and have fun! ヽ(>∀<☆)ノ