Blocks and items added are as follows:
The Gold Hopper transfers items fast, though has lower inventory space
The Copper Hopper has a high inventory space, but transfers items slowly. There are no functional differences between oxidation variants
The Iron Pipe has a single slot and can only transfer items straight down, but transfers 16 items at a time
Copper Pressure Plates are player only pressure plates, and oxidation increases the time the pressure plate stays down
Light Detectors are a more specialized daylight detector that has three modes
Copper Grated Redstone Components are grounded against water. In-game this means that these components don't get washed away by liquids like water or lava, and can be waterlogged. These components are otherwise functional to the same degree as their base components, and can additionally be oxidized.