Power to the players
(2019-05-03) If X is 10 or more, the creature card you just put onto the battlefield will get +X/+X and haste
BPhillipYork: It's a 10/10 with trample that can sacrifice enchantments and gets cheaper when you have enchantments
There may be others out there, but these are the big ones: classified ads (of which Craiglist is likely the most popular), Ebay, and your Magic social circle (this includes Facebook groups, friends, local gaming stores, and players in your local area)
Elspeth is hard to kill, you need a decent board lead and ideally a range of dorks with a range of evasion
If Gisath resolves, it will absolutely take over the game, and it has the ability to race any deck by potentially bringing multiple Dinosaurs with it when it attacks the turn you cast it