It gains indestructible
Since you get to leave your foes with their worst creature while you get your best, it's extremely likely The Eternal Wanderer will survive her ultimate, especially as she can only be attacked by one creature at a time
The 30th and final card you'll have to find is the Shiny version of Mega Shine's animated 3-Star Mew card
Pumping up Legolas with +1/+1 counters is helpful for making his second ability pay off, though green mana also has plenty of enchantments that can boost Legolas' power and toughness regardless of counters
If you need extra Credits, try picking up 400 codes of a set that you havent collected on Live yet, like Sword and Shield, to get a bunch of extra Credits (and cards to complete your collection)
When we are talking about Alpha, Beta and Unlimited, we always have to keep an eye open for the Old School format