Most decks can answer them in some form. This design philosophy becomes apparent on Barbflare Gremlin, a brand-new creature that appears in this deck, which combines the rules text from two older enchantments, Manabarbs and Mana Flare
You use his Boost ability to put a card under him
It was so powerful that it was the best card in the Invasion block, including the rares
Some players consider cards like Dark Petition and Priest of Gix to be rituals as well, but I think you need to come out ahead on mana for a real ritual effect
If Mufasa survives, you can use all of your ink, quest for 4 Lore, and then use all of that ink again
They were playable when I was playing the TCG locally