In rarity, SP cards sit below ultra-rare Manga Rare cards but above standard alt-arts typically one SP can appear in 5-6 booster boxes, whereas a Manga Rare is far more elusive (usually only a case hit)
Similarly, you can't waive a cost reduction unless that effect says you may
In D&D, metallic dragons (bronze, copper, brass) are in opposition to chromatic dragons (red, blue, green, etc.), chromatic being the typical evil, sometimes cruel and selfish dragons while the metallic dragons are mostly altruistic and righteous creatures
Tireless Tracker is a great way to draw cards as this Human Scout not only creates Clue tokens, but has the potential to grow quite large as she accrues +1/+1 counters each time you sacrifice a Clue
The Meathook Massacre Another interesting card to come from Innistrad: Midnight Hunt is The Meathook Massacre