Linux Mint have created a GTK Frontend for GNOME Online Accounts, now that GNOME's version of this requires libadawaita. It will be in the next Linux Mint (22 due in the summer), and is already in the Arch AUR and Debian Sid repos.
Original Icon: The hicolor icon is the same as that for cs-online-accounts, so creating a symlink in Papirus would be straightforward & consistent (rather than having to create a new icon).
Linux Mint have created a GTK Frontend for GNOME Online Accounts, now that GNOME's version of this requires libadawaita. It will be in the next Linux Mint (22 due in the summer), and is already in the Arch AUR and Debian Sid repos.