Deprecated use this one instead: https://mods.factorio.com/mod/Infinite_Repair_Pack_Revived/

This mods adds a repair pack with infinite durability, the Sonic Screwdriver (a reference to Doctor Who and old Factorio). Available for research after Automobilism, slightly more expensive to produce, and repairs at the same speed as the vanilla repair pack. Not really overpowered since the vanilla repair packs cost almost nothing to make anyway just a small quality of life addition.

Update:
0.1.1 - More expensive but repairs faster to compensate. Made compatible with Industrial Revolution and maybe other overhaul mods. (Note IR automatically adjusts the technology cost to be far more expensive to research. Nothing I can do about it.)