IMPERIAL KNIGHT units from your army have the following the ability:

Sacristan Pledge: In your Command phase, one model in this unit regains 1 lost wound. If this unit is within 3" of one or more friendly TECH‐PRIEST models, one model in this unit regains up to D3 lost wounds instead.

ADEPTUS MECHANICUS units from your army have the following ability:

Divine Inspiration: Each time a model in this unit makes a ranged attack, re‐roll a Hit roll of 1. If this unit is within 6" of one or more friendly IMPERIAL KNIGHTS units, re‐roll a Wound roll of 1 as well.