Using ROP:Infernal and its maleficia rules:
The leaden amulet - using Debauchery/Consumption General guideline, this level 15 effect adds +1 to damage and soak, and adds 1 point to the wearer's load. (5 points for 1st magnitude, +1 touch, + 1 diameter) - each +5 levels increases the bonuses/penalty by another +1. There's also an effect to add magnitude to Initiative,attack and defense with the same penalty to fatigue rolls - but I rarely make fatigue rolls in 5th edition so I suspect this is broken.
The cursed sword - Incantation Consumption 25 (base 20,+1 touch) heals a medium wound belonging to the wielder, and inflicts a medium wound on the victim. Adds a certain edge to combat, and the higher level versions get particularly deadly.
The witch's wand - Debauchery/Diablerie 20 (base 4, +3 sight range, +1 diameter duration) - pointed at a victim within sight, for the next 2 minutes the wand counts as an arcane connection to the target. Handy for boosting your penetration.
Protect me from my rival wizards - Incantation/Diablerie 15 - (base 5, personal range, +2 sun duration) - gives the caster a magic resistance of 10. Handy for allowing moderate infernalists to challenge starting magi.