Yeah, Terraria is a great example of a game where the grind is integral to the game. Needing to get 20 drops from a particular creature encourages you to explore the specific zone deeply enough to really enjoy it. There's no story to progress through, it's just exploration and grinding to get different materials.

Similarly for Minecraft. Is it "grinding" to mine diamonds at z-level 11, or is that the game?

JRPGs and MMOs are the ones who generally don't respect your time with their XP grind systems.