An official Japanese Pocket Monsters Twitter account has completed a Ball Guy (ボールガイ) code distribution. The codes can be redeemed from December 19th, 2019 until January 15th, 2020 by entering the code in the Mystery Gift option in Sword or Shield.

ballman

Image Code Items Notes
symbol K0UN1NMASC0T Fast Ball, Moon Ball, Level Ball 公認マスコット translates to "official mascot".
symbol 1YAHAYA Heavy Ball, Lure Ball, Beast Ball いやはや in the context of these games means "blimey".
symbol 0KUGAFUKA1B0RU Love Ball, Friend Ball, Dream Ball 奥が深いボル translates to "they're more than meets the eye, b'all"

Source: https://twitter.com/poke_times