The Asterisk Chest holds one stack of items of a specific type. Right-click with an item to set the type. Might be useful for sorting systems. This block has no gui, so there's no simple way to see how much is in it.
A Cobblestone Generator in one block! Use any item extraction method (e.g. hopper) to collect cobblestone.
The Digital Cabinet is similar to a chest, with a few advantages. It has 9 extra slots, it doesn't require an empty space above it, and all digital cabinets above it are considered part of its inventory to hoppers, etc.
The Obsidian Pressure Plate is a pressure plate made of obsidian. It only detects players.
The Player Interface acts as the inventory of the player that placed it. You can insert and remove items using hoppers, etc.
The Redstone Activator will right-click on the block in front of it when given a redstone signal.
The Remote Inventory acts as the inventory it's bound to, provided that it's in a loaded chunk in the same dimension. Right-click while sneaking to set the target inventory, and right-click to place the remote inventory. Right-clicking on the placed block will redirect the right-click to the bound inventory.
The Block Sucker can inhale blocks and tile entities, and place them in another location.
The Entity Sucker can inhale entities and place them in another location, provided that you can right-click on the entity.