what is better than, or similar to, flak jacket?

Bleed intercept + damage prevention = useful (it costs 2 pool though)

Guardian Angel

Master.
Cost:2
Put this card on a ready vampire you control. This vampire gets +1 intercept when you are being bled. This vampire may prevent 1 damage each combat. Burn this card if this vampire goes to torpor.

Edit: I feel the pool is worth it. If I am willing to take an action and pay a pool for a Flak Jacket or a Kevlar Vest, then it seems worth it (to me) to use a Master Phase action and 2 pool for the prevent and the intercept.

Ashur wrote:

There´s also that Toreador retainer.

Name: Resplendent Protector
[Jyhad:R2, VTES:R, CE:R]
Cardtype: Retainer
Clan: Toreador
Mortal with 1 life.
The minion with this retainer may prevent 1 damage each combat.

the one flaw with this retainer is he's only good for guaranteed close range combat. at long range they'll just shoot the protector, so he only prevents damage once in his lifetime.
Hatch the Viper is a similar card, though with extra bonus damage.

in some situations, Blood Tears of Kephran can be a lifesaver.

I do like stacking Flak Jackets sometimes as insurance against 2 agg instead of 1. for example, Outside the Hourglass.