Its super weird that the only one mana Ninja designed to get through so your other Ninja can sneak in is a green creature
These creatures from various blocks all served the same purpose as the Study/Gift, but at the cost of one card and three mana (or four mana in the case of Stinging Barrier)
For Riveteers Charm's first mode, if the target opponent controls more than one creature or planeswalker with the highest mana value among creatures and planeswalkers they control, that player chooses which one to sacrifice as Riveteers Charm resolves
You can choose a common number for MV, power, or toughness and whenever an opponent plays a card with that number they take damage and you draw a card
Even against battlecruiser decks, it often finds a target in their mana rocks, disrupting their curve
This ability means that Dinosaurs are encouraged to fight in every way they can, whether through attacking and blocking during combat or using actual "fight" cards like Savage Stomp