Just answered my onw question:
Not counting starters, (only gen 3 and 4 released, so add a 5, but event only) and the Legendaries from Dream Radar (Altered form Lords, Ho-Oh and Lugia). families' hidden abilities could become rare. That is not counting any family without a hidden one.
They are mostly the unavailables without transfer, fishes and fossils.
The list:
! Cute Charm: Milotic
Analytic: Porygon Staryu Patrat Elygem
Big Pecks: Chatot
Chlorophill: Cottonee
Damp: Horsea Frillish
Frisk: Sentret
Gluttony: Munchlax
Hustle: Rattata
Hydration: Barboach Luvdisk, Clamperl-Gorebys
Inner Focus/Zen Mode: Darumaka
Intimidate: Qwilfish
Keen Eye/Defiant: Glameow
Lighting Rod: Goldeen
Limber: Buneary
Mold Breaker: Basculin
Overcoat: Pineco, Burmy-Wormadam, Shelmet, Excavalier
Tinted Lens: Mothim
Unburden: Accelgor
Pressure: Wailmer
Quick Feet: Zigzagoon
Rain Dish: Tentacool
Alomomola: Regenerator
Technician: Kricketot
Sand Force: Hippopotas
Sap Sipper: Stantler
Sheer Force: Cranidos
Shell Armor: Torkoal
Soundproof: Shieldon, Boufalant
Speed Boost: Carvana
Storm Drain: Lileep
Sturdy: Relicanth
Swift Swim: Anorith, Tirtouga
Unnerve: Meowth, Aerodactyl
Water Absorb: Chinchou
Water Veil: Gorebys, Mantine, Finneon
Weak Armor: Kabuto, Omanyte
Wonder Skin: Skitty
Interesting: Chinchou, Anorith, Lileep, Carvanha, Stantler, Cranidos, Tentacool, Kricketot, Alomomola, Burmy, Elygem, Barboach, Gorebys, Qwilfish, Accelgor and Goldeen.
I should have searched in reddit before spending an hour of my life doing this.