frozen caves underground biom

generating instead of lush caves in freezing/cold biomes
generates with ice blocks of all three types (standard, blue, packed) in various formations, something like icebergs could generate in there
icicles, working similarly to pointed dripstone, generating on roofs and ground, growing when under ice block variant with water above it, harming players when landing on it or falling on them, 4 of them craftable into ice block
icy berries, saturated light blue color, almost like neon color, berries on bushes growing on walls of cave, bluish-green leaves of bushes would somewhat blend in cold biom, berries emitting little of glow, when consumed, applies freezing effect similarly like standing in powdered snow does, possibly used in some potion or meal with beneficial effects, or having another use entirely
permafrost blocks would make walls and floors of cave, bluish stone-like block, texture similar to dripstone (except color of course), craftable into light blue bricks, chiseled bricks, walls, stairs and other usual stone variants
fossils would have higher chance to generate inside of permafrost in frozen caves