Pigs, Striders, and Horses check if they are in blocks such as bubble columns another time near the end of the tick. This applies while the player is riding these entities, but does not apply to the player itself.
This has the same hitboxes as a sea pickle.
Added Candle cakes:
This has the hitbox of a cake with an additional hitbox on top for a candle.
Added Sculk Sensors:
This has the same hitbox as a bottom slab.
Added big dripleafs:
The hitbox of this block varies based on its tilt, which is affected by players standing on this block.
It can be stood on for 20 ticks, before it tilts once and lowers its hitbox slightly . This is calculated server sided.
After another few ticks, the block's tilt will change once again and the block will have no hitbox . This is calculated server sided.
The leaf will immediately fully tilt if hit by a projectile. 
The hitbox of this block varies based on its thickness and vertical direction, and is also offset randomly with the same fixed formula as bamboo.
Unlike bamboo, this block can be offset no more than 0.125 blocks from its original position.
Added powder snow:
Entities with more than 2.5 blocks of fall distance will have a hitbox with a height of 0.9. The stuck speed multiplier will reset fall damage and the entity will fall through the next tick.
Entities with leather boots will have a full block hitbox, as long as the entity's Y position is above the top of the block.
Entities with leather boots are able to climb this powder snow.
Otherwise, this block has no hitbox and the player will fall through.
Staying in powder snow will slow the player.
However, when the player is on an air block, the slow effect will be cleared at the end of the tick, regardless of what the server tells the client
The client will apply its own slow effect at the end of the tick, based on the server controlled frozen ticks metadata.
The server also sets the frozen speed reduction attribute, applied at the start of the tick which overrides the client's previous tick. Leading to unpredictable speed.
Entities in stuck snow get a stuck speed multiplier of (0.9, 1.5, 0.9). This means the player will move slower horizontally but can jump higher in powder snow than they otherwise would be able to.
This block has the hitbox of a top slab with an extra hitbox beneath to represent the stem.
Added amethyst clusters and buds:
The hitbox varies between clusters, small buds, medium buds, and large buds.
Bugfix: Standing on top of a boat will no longer rapidly teleport the player.
Bugfix: Buckets will no longer desync with rapid looking, although they can still desync over a high latency connection.
The player's block coordinates must be in water for them to start swimming. This fixes players rapidly switching between swimming and not swimming state when only their heads are touching water, and not their feet.