Some Eaglercraft versions (especially older ones) allow texture packs that make stone and dirt transparent.
: Xray Ultimate is a widely used resource pack that is compatible with version 1.8. xray hacks for eaglercraft
: Makes Stone, Dirt, and Sand invisible while keeping Diamonds, Gold, Iron, and Ancient Debris fully opaque. Fullbright and Sand invisible while keeping Diamonds
No coding, no bans from Eaglercraft's anti-cheat (if done on a single-player world), and very hard for servers to detect. Cons: You can't see caves easily, and movement is disorienting because you see the void. xray hacks for eaglercraft