The first ability is very similar to the ability on Runaway Steam-Kin but with Birgi, the mana is available right away instead of having to cast three red spells for Steam-Kin
BPhillipYork: This would really make a green/white + anything else you want enchantment deck pop off, since early game you can use enchant lands for ramp, then drop this and cast some really expensive enchantments, truthfully though the really expensive enchantments aren't that good
Whenever a creature you control attacks or blocks, it gets +X/+X until end of turn, where X is the difference between its power and toughness
SHADRIX SILVERQUILL Perhaps Im just more critical when it comes to my darling WB color combo, but just like Silverquills Deans, this Elder Dragon leaves me with mixed feelings
Compared to Sower she is more robust due to having persist however most of the time you want to make this guy with a mana open as tapping out to drop a 2/2 you don't want involved in much combat and therefore doesn't offer much tempo can be very risky, it can easily lead to them untapping and getting out the card they were holding back for fear of other counters