Flashback is typically used to add some super late game value on to otherwise fair early game cards
They are also ideal for a variety of Magic: The Gathering cards, including Planechase, Vanguard, Archenemy, and Commander cards
But if you live on a busy street and the weather is nice, you might be able to sell out all your cards and other items for a nice lump sum
Earthshaker Giant I rate this is a bit better than End-Raze Forerunners but not much, one spot better, since it's cheaper for a smaller 6/6 with trample too, but gives your team trample and an additional +1 size
Look the top 3 cards of your opponents Deck
Swinging Sphene is a less certain, but still very deadly attack, requiring 1 Grass, 1 Water and 1 Fighting Energy to use