Hololive as a whole:
Hololive 2023 Shuffle Medley - members swapping signature songs and outfits
Hololive 2024 Shuffle Medley
Seishun Archive
Adventure Holic (I don't know how to make a heart symbol)

The defacto anthem for the entire company:
Shiny Smily Story (2022 version, this one)

Units, waves, branches, etc;
Holotori Dance a collab between the five bird(and bird-adjacent) members of Hololive across all three branches~
Mind Craft a project Bae financed, featuringg all 15 current members of the EN branch
ReUnion Hololive English MYTH full group song
NonFiction Myth's anthem
Journey of a Thousand Years

Inugami Korone:
Korone doesn't do a lot of singing, but what songs she does are either somewhat silly and high energy or covers of video game music. A true gamer doggo~
Original:
Wonky Monkey
Doggy God's Street
Kawaiko Check!
Wonderful World of Korone
Covers:
Pollyanna (Earthbound/Mother series)
Fire Emblem theme/commercial song(With special guests Kanata and Okayu)
Bomber King (With assistance of her GAMERS genmates~)
Airman ga Taosenai (I can't beat Airman) from a HoloFes concert, video on Bilibili
Collabs:
Not sure what this is called, but it's Okayu and Korone
Bite! Kamu! Bite! - with Hakos Baelz

Tsunomaki Watame:
Watame does a LOT of singing, and a lot of her stuff has music videos, so I'll just link her full Original Music playlist here and point out some favorites of mine
Now On Step
What An Amazing Swing
My Song

Hakos Baelz:
Bae, as pretty much everybody calls her (Or 'Hakotaro') doesn't do a long of songs, particularly solo, but here's her signature one
Play Dice

Houshou Marine:
Marine is...unbelievably horny, and many of her songs reflect this, such as
I'm your Treasure Box
Shinkiro (With Gawr Gura)
'Beautiful Innocent Pirates' apparently
But also, she's a boomer nerd who has done
Bloody Stream
and her previous signature song
Ahoy!

Mori Calliope
The Rapping Reaper, Calli mainly does rap, and is extremely prolific - she's even signed with Universal Music Group Japan!
Her music playlist just because there's SO MUCH, but here's some choice selections from me
'Q' a collab with Gura, thought to be a kind of spiritual prequel to their cover of
King originally a vocaloid(?) song, sung by what seems like half of all vtubers, Calli and Gura put their own spin on it
Nezumi Scheme
Internet Yamero (English version)

Gawr Gura
Gura's not the most prolific singer, but is an exceptionally good one still. Many of her songs are in her karaoke streams (Really, almost everyone does Karaoke streams, but Gura has some special songs, such as
Sabaton's 'Resist and Bite' and
The Last Stand

There's a bunch more, of course, and even a bunch of non-Hololives I do follow for music, but I've had this post open for like eight hours now, and I never meant for this to get this extensive. So come on down with your own~