Rare off-sales under 75 owners. Will update list every once in a while.
Recently the valentine items were taken off-sale, so a bunch of items to add.
Please LMK of any that I've missed. Mystery items are all together, and the items must be non-rare, off-sale, and under 75 owners.

Absolute Shutdown - 64 owners
Smoochy Face - 59 owners
Blue Star Face - 55 owners
Arrow Through Chest - 50 owners
Love Halo - 50 owners
Mystery Box #1 - 45 owners
Valentines Boppers - 40 owners
Valentines Bow - 40 owners
Overlord Antlers - 39 owners
Water Balloon Launcher - 37 owners
Mystery Box #2 - 34 owners
l33t Hacker's Fedora - 33 owners
Evil Bobby - 30 owners
Minty Fedora - 28 owners
Love Shades - 27 owners
Discerning Sicarius - 25 owners
Dove on Shoulder - 24 owners
Astronomical Planets - 23 owners
Astronomical Helmet - 21 owners
Overlords Sicarius - 9 owners