Migratory Greathorn is the second of the three, and it does a fantastic job of ramping your mana on mutation
Thats not an unachievable amount of mana to generate, be that in Limited or EDH
And this set a precedent, as flavor would go on to be one of the primary reasons that typal coupling is used
When it comes to Item and Action cards, these should collectively make up one-third of a deck , generally
Mythic rares tend to be more expensive than rares
Though power creep has surely made this six-mana creature somewhat obsolete, it is still notable for being a dual Magic lord, boosting both Treefolk and Saproling creatures, and it also serves as an effective mana sink via its kicker ability, which can be used to invest when you cast it, which will creature that many Saproling creature tokens