In my
Lazav, the Multifarious voltron deck I always tutor for
Buried Alive, or for
Intuition if I already used BA and/or if got my graveyard exiled. Though I guess that's not entirely the correct answer since
buried alive is also a tutor in its own way.
When I use it I always tutor for
Phyrexian Dreadnought and
Vector Asp for that sweet sweet one hit kill combo. The 3rd card is trickier, if I have no defense in my graveyard I have to think about protecting Lazav, in which case my go to target is usually
Thassa, God of the Sea. If I already have something to protect lazav in there then my other choice is
Invisible Stalker for the hexproof / unblockable.
With Teysa I tutor for
darkest hour if I want to win right away, and when I'm playing casually / for fun I usually target
Anointed Procession for all that sweet value. I also had some very casual games in which I tutored for
Smothering Tithe just for fun (it's one of my favorite cards ever and it's just so satisfying to play).