I found this INSANELY large lush cave. It has a giant deepslate pillar and many small caves connecting to it. I thought it was really cool, so I'm sharing it here (Java Edition only)
Seed: 2314462785052804730
Co-ords: 350, ~, 206
Note: When creating the world, set world type to Single Biome and click Customize. Then select 'Lush Caves', enter the seed and load up the world! Enjoy!
-dismal
Source: https://www.reddit.com/r/Minecraft/comments/m2pmzv/huge_lush_cave_snapshot_21w10a_lucky_find/