Merry has some live-only songs as well. I've got an old tereko from around the time of Gendai Stoic's release featuring a song I haven't been able to identify, and I don't think it's ever reappeared anywhere else. There are also a few later tracks from the 2010s that don't seem to have been properly released, like this one for instance:
https://www.youtube.com/watch?v=AiecDx9pFRw

There's also that sludgy version of Violet Harenchi that was featured in a tour promo video at one point, but nowhere else. Might be that these were live-only privileges or FC material, but I don't know for sure.

Aside from hakai to souzou, they also released "people" for the first time as a venue-exclusive single back in 2024, and there were two songs performed on the 2023 EBISU LIQUIDROOM blu-ray that were previously unreleased, but still have yet to be released in studio form: "kagoniwa" (籠庭) & "kagi wo kakenai heya" (鍵をかけない部屋). Kagoniwa is a big favorite of mine so I'm really hoping they give it a proper release at some point...

Aside from those though, there are a few more yet-to-be-released songs that I'm hoping make an appearance some day in the future... "CANNIBALISM" (カニバリズム) & "LOVE ME"... there's a bit of information about them on old fansites, & what I find most noteworthy is that CANNIBALISM was apparently composed by maco himself, which I don't think he's done at any other point in his career, as far as I remember... there are old transcribed lyrics for both songs here, it sort of gives you an idea of what kind of songs they were... very interesting.

This other fansite describes both of those songs, as well as two others that, according to the site owner, were performed only once at a show @ Nagoya Music Farm before unfortunately being shelved: "sabbat" & "watashi no naka no aoi kumo" (私の中の青い雲). That's literally all I know about those & I really wonder if they'd even consider bringing them back. Well, I guess it depends on whether they've got any old footage of the performance since apparently maco has lost all the original lyrics he wrote and has had to go thru and transcribe them manually using old recordings they own LMAO .

And... I know buruubejii is technically released as it went on to become a deadman song, but I'd love to hear the original kein version get some sort of release someday too... I think I remember seeing setlists with the song on it as recently as 2024? So I guess they're playing it live. Given how similar the composition and lyrics were to the eventual deadman version though, I can't imagine they'd include it on like, the next album or anything like that... Maybe we can hear it on a blu-ray at least... or another venue-exclusive single : P

I can think of quite a few other bands with unreleased material, though... it might be cheating for me to bring up GULLET's "rakujitsu" since it was later released as a 9GOATS song on the limited edition of Sleeping Beauty, but I just can't imagine how the GULLET version might have sounded... it's one of ryo's favorite poems according to his final entry on the GULLET diary though I think about that so much...
I did find this fansite that has a list of unreleased GULLET songs though... really neat. I can't remember exactly, but I think there was also an unreleased Galruda song that went on to become a GULLET song...? Maybe someone else knows more about all that...

Also worth mentioning, my favorites MUNIMUNI always have like a big chunk of songs they play live, which either end up on releases later or not (or yeeaaars later, lol). Right now if I count it right based on their diligent online setlist archives, they have about a full album's worth of unrecorded tracks. They're in the middle of recording a new album though, so we'll see how much will end up there.