After all, my pick for best one-drop white creature of all time is Thraben Inspector (over Mother of Runes), where the kicker is that extra toughness
Basic Pokmon are like babies and are first in their line
Land Color tag templates(None) Color tag templates(None) Terramorphic Expanse , Sacrifice this land: Search your library for a basic land card, put it onto the battlefield tapped, then shuffle
Cait, Cage Brawler offers discard, but not much else
While not as immediately explosive as Elsha (or the original Mentor), it makes up for that with the innate stickiness of enchantments and a steadily-scaling return
With even normal Enchanted Rare cards only estimated to appear in roughly one in 100 booster packs, finding an Enchanted Rare Discard card is like hitting the jackpot in the lottery by comparison