houshou marine, shirakami fubuki, hoshimachi suisei, usada pekora, nekomata okayu, and 31 more (hololive and 3 more) drawn by koga_rejini

Artist's commentary

Original

【C97】でふぉロライブ

C97で頒布するホロライブカレンダーのイラストです～。
ホロライブ・イノナカ・ホロスタ１期生まで全員入れました！
（委託はコチラ　https://www.melonbooks.co.jp/detail/detail.php?product_id=610452）

イベントに関する情報はツイッターが一番はやいので良かったらフォローしてください！
https://twitter.com/koga042

I can spot a few particular references, which makes me think that there's actually a crapton of references in here and I just don't know about them.

A few references straight from the Holograffiti shorts: Roboco's arm, Ayame in a shark, and Akirose and the puddle of poison
The washtub is probably from Pekora's 3D stream. Not completely sure about the Minecraft trident, but it reminded me of the time Miko chased her around.
Suisei is being Suisei as always.
Matsuri is doing the Matsuri face.

A lot of other things seem like they're referencing something specific, but I don't have enough encyclopedic knowledge to say for sure, especially since I still don't know much about the Holostars crew.