I don’t think these include mint specific packages like OP wanted?

I’m on mint, these are my package mirrors (based in the Netherlands):

/etc/apt/sources.list.d/official-package-repositories.list

deb https://mirrors.evoluso.com/linuxmint-packages/linuxmint-packages zara main upstream import backport 

deb http://ftp.snt.utwente.nl/pub/os/linux/ubuntu noble main restricted universe multiverse
deb http://ftp.snt.utwente.nl/pub/os/linux/ubuntu noble-updates main restricted universe multiverse
deb http://ftp.snt.utwente.nl/pub/os/linux/ubuntu noble-backports main restricted universe multiverse

deb http://security.ubuntu.com/ubuntu/ noble-security main restricted universe multiverse

afaik there’s no public list of package mirrors