Let's count the infinite combos that you can start with a Sliver Queen, shall we? 1. Sliver Queen + Mana echoes: Infinite mana + Infinite 1/1 Creatures. 2. Sliver Queen + Ashnod's Altar + Heartstone: Ditto above. And that's just with one of the slivers. But I've found a few wicked sliver combos without any other cards. 3. Sliver Queen + Gemhide Sliver + Heart sliver + Basal sliver: Infinite mana. Add an acid sliver onto that for infinite damage, or a darkheart sliver for infinite life. And don't get me started with cloudstone curio!