Ok, these may or may not be right, I'm just looking thrugh my groups and either they changed rarity or I've misplaced them by accident. If anyone wants to confirm/disprove, go ahead.
Common -> Uncommon
(I think there's a 3rd one of them but I don't have it and I don't know if it changed rarity as well or not.)
Uncommon -> Rare
Very Common -> Common
Man... I really hope I didn't mess all my groups up That's a lot of rarity changes...