Uncapping the mana available to players at the start of the game makes it more reasonable to allow potent attacks on mana, like Wasteland, Daze and Armageddon, adding a whole new strategic element to the game
The arcane subtype has more influence on other cards, like spells with splice onto arcane, or cards with abilities that trigger when arcane spells are cast
It's unclear whether this was the most necessary of the Slivers, but it was the one that frustrated the most opposing plans to deal with the problem and even opened up new game plans when the card advantage resulting from saving your creatures could allow Sliver decks to go the control route when backed up by counters and removal spells
#3 Skithryx, the Blight Dragon Skithryx, the Blight Dragon is a reprint that MTG players have been fervently requesting for quite some time
Firesong and Sunspeaker's last ability doesn't trigger if a triggered ability of a white instant or sorcery spell or card causes you to gain life, such as the triggered ability of Renewed Faith when it's cycled
In a deck that can get some absurdly strong creatures and loves to have extra mana, Selvala is an auto-include in your Druid Kindred deck