One such card was a green mana flare
You can adjust this number as needed, but 40% should be what you run in any given scenario, regardless of the format
C Common Libromancer First Appearance X SPELL Field When this card is activated: You can add 1 "Libromancer" monster from your Deck to your hand, with a different name than the cards you control
The primary goal of Explore is to either get cards you don't want (or do if you're short on lands) out of your deck and out of your way
In addition, the bottom of the card will have a textbox reading " TEST CARD - Not for constructed play ." The art is also often of lower, sillier quality as it is done in-house by R&D members rather than commissioned artists (hence the lack of artist credit on the cards)
Again, there is a caveat to its attack attempt , which may just work quite quickly to get what you need to defeat your opponent