Whether you've seen them in action or are just theory crafting. What are your favorites?

Mine:

1) Blade Champion leading Custodian Guard. The Blade Champion allows the Guard to Advance and Charge with rerolls in the same turn that that they double shoot. The Guard give the Blade Champ wound rerolls which works especially well with with Sustain 1 on Victus to dole out a few mortals against vehicles. This is a fast and painful unit!

2) Sheild Captain leading Allarus Custodian. I'm not seeing people mention the ability to double Rapid Ingress from Deep Strike, which is bonkers. This can be done with any infantry unit, yes, but I like it more with Allarus as it makes an excellent Character killer, and you can plot the unit on a back objective T1, Free strat to lock it down, Deep Strike out, and free Ingress back down later.