Glad you asked, from wikipedia
>Evergreen keywords
>These are keywords which may appear in any Magic set, particularly the Core Sets where they are usually the only keywords. They are also used in many expert-level expansions, but in those sets they are printed without reminder text.
>For example, deathtouch, haste, trample, flying.
Now that we are on the subject, analize the following changes that would make Hearthstone a much better card game:
DISCOVER mechanic becomes evergreen.
SECRETS mechanic becomes evergreen and all classes gain access to them.
Neutral cards moved to Classic
>Nerubian Egg
>Sludge Belcher
>Loatheb
>Zombie Chow
>Reno Jackson
>Sir Finley Mrrgglton
>Justicar Truehearth (all the powers are re-ajusted for balance)
Hunter cards moved to Classic
>Webspinner
>King's Elekk
>Steamweedle Sniper
>Call of the Wild
Paladin cards moved to Classic
>Muster for Battle
>Shielded Minibot
>Keeper of Uldaman
>Anyfin Can Happen
>Murlock Knight
Druid cards moved to Classic
>Darnassus Aspirant
>Living Roots
>Raven Idol
>Fandral Staghelm
Warrior cards moved to Classic
>Death's Bite
>Grim Patron (becomes Warrior class only)
>Alexastra's Champion
Mage cards moved to Classic
>Arcane Blast
>Flamewalker
>Mad Scientist (becomes Mage class only)
Priest cards moved to Classic
>Deathlord (becomes Priest class only)
>Velen's Chosen
>Lightbomb
>Dark Cultist
>Museum Curator
Rogue cards moved to Classic
>Tinker's Oil
>Unearthed Raptor
>Tomb Pillager
>Undercity Huckster
Shaman cards moved to Classic
>Ancestral Knowledge
>Lava Shock
>Tuskarr Totemic
>Totem Golem
>Tunnel Trogg
Warlock cards moved to Classic
>Imp-losion
>Demonwrath
>Dark Peddler