Like most Pokmon cards, the value of Steelix GL depends on a few consistent factors: its rarity, the printing and finish (regular or foil), its physical condition, and the set it was printed in (Rising Rivals)
What drives a Pokmon cards value Rarity: how few were printed and how limited the distribution was Condition and grading: the assigned grade, with PSA 10 and BGS 9.5+ at the top Edition: markers like 1st Edition, Shadowless, or No Rarity Symbol Errors: recognized printing flaws that add scarcity Where to Check Current Card Values If you want to know what your own cards are worth right now, a few resources give you a reliable read on the current market
Displacer Kitten also gives you the ability to target non-land permanents like Brago and Yorion, but its flicker clause only triggers when you cast a non-creature spell
Given the mana cost and the fact that it's not always a 4/4, I doubt you'll see this as anything more than a 2-of, but the potential definitely feels like it's there with this one