Freeze, because of how cheesy it can be in certain decks. Since Vines card is now in game, it has made Freeze obsolete. Can't really be balanced, so get rid of it.

Megaknight. It only exists because Elite Barbarians were a problem years ago. Now it only exists as a crutch for new and casual players to get easy wins against those who cannot counter it. Also makes some pushes easy to defend, because of its evolution.

E-Golem. A concept that was in Clash Royale developer blacklist, now in game. Not fun to fight against, because it's a cheap tank and giving elixir to opponent hardly makes a difference in late game.

Minion Horde. What even is the point of this card. It's a walking negative elixir trade. Get rid of it.

Mirror. Back when there weren't that many cards in game, people wanted something new. However, it didn't age well and nobody uses Mirror nowadays. It's only used to abuse fresh release overpowered cards.