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)
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!