Ag4tr

Wearing this suit you can roam around the nether without the worry of burning in the lava or scuba dive without the risk of asphyxiating! Charge it up for the cooling bit to work (power is only required when you're in lava, flame protection is passive) and keep cells of compressed air in your inventory for you to breathe underwater! One canister grants you approximately 24 seconds of air. The suit requires a little bit of power to swap the canisters, too. For realism sake. Only the chestpiece and helmet are needed for scuba diving, for fire/lava protection you need the full suit (that is, the helmet, chestpiece, bottoms and rubber boots).

See in dark places at the cost of energy with this state-of-the-art light-amplifying apparatus!

Toggle with a hotkey, N by default.

Resist knockback with this set of rubber armor! It's a tad better than leather armor and each piece gives you a bit of knockback resistance.

Stun your mobs with electronic stick! Simply hit them once its capacitors are full. Each charge takes 256 E (configurable). Entities get stunned for ~6 seconds (configurable), during this period, they are significantly slowed down and weakened. Arachnids receive heavy damage from it (configurable). Creepers explode when shocked with this (configurable).

You switch the taser on/off by shift-rightclicking with it in your hand. When it's on, it will consume some power to charge its capacitors. After ~5 secs (configurable), it will be usable.
There's an capacitor charge indicator in the taser's tooltip. Grey means that the capacitors are empty, yellow means partially charged and not yet usable, green means fully charged and usable.

Your go-to hip dislocation prevention tool! Significantly reduces your fall damage with each fall at the cost of taking a bit of a beating.