kawaii sign

or kawaii signature. A Japanese term for signatures with cute elements on them, usually having complex analogies of letters and shapes (usually animals). Popular in VTubers (mostly Japanese-only) and Kpop communities, both fans and the music band members

Used colloquially in Japan (they use hanko in formal context), but sometimes used as formal signatures outside Japan

There are some or a few people who makes kawaii sign commissions if you search for "kawaii sign" in Katakana letters and they all, the examples, looks catchy. I discovered it from a random VTuber/streamer in my Twitter recommended accounts and she did retweeted or tweet about who made her kawaii sign