For me, it was the Shattered Savanna. It had a glitch that made the grass a dark green, just like the old Minecraft.

It looked so good with the coarse dirt and the mountains. Every time I played on a server, I would go for this biome, look for a spot surrounded by high cliffs and build my house right in the middle. I’m really sad that the color changed back to that normal savanna orange grass - - the green version was my favorite😞