A wither aconite produces mana that is collected by the mana collector and transported into a pool via sparks. The hellebore uses that mana to stop the piglin from zombiefying in the overworld.
The raindeletia produces mana as it's raining. This mana is used by an aquapanthus to fill a petal apothecary.
The alfsteel pylon can repair alfsteel tools for half of the mana it costs when repairing them through a mana tablet in your inventory. It can also repair mending tools for mana.
The armor makes you for example faster and jump higher.
You can also create terrasteel on this plate.