It varies for me. When I first started playing I was all about Scarabs, and that was before I'd even heard of a Pharoh. Now I can't imagine how you'd play a good Scarab hand without Pharohs.
I then moved on to
, although I've never really gone down the Devourer route. Vampires all the way, although I always tended to use unupped Vampires, so that they couldn't be killed by Maxwell's Demons.
I then moved on to
, enjoying the invulnerability of Phase Shields and adoring both the cheekiness and unpredictability of Mindgate.
I then decided to go for even more unpredictability with a hand which is as random as possible, consisting of Fate Eggs, Shards of Serendipity and Druids. Great fun to play, but not much use above AI3.
Nowadays I usually farm with a rainbow, using
and Supernovas, but I tend to play
or
when I've achieved my
goal for the day.* At the moment I'm enjoying Mindgate again, but I'm also working on a mono
deck, a
/
Vampire/Adrenaline deck, and a
/
poison deck. I've also got a
/
Scavenger's Cat deck which I dust off every now and then. And I've just won a
Nymph, so I'm starting to think about building a
deck, which might be useful as an anti-rainbow farming deck.
So, long answer short - it depends on what mood I'm in, but there are elements I favour above others. Over all my favourite card is probably Shard of Serendipity because it ensures a different game every time, even if it takes a while to set up.
*I'm slowly working on getting everything, 6 upped and 6 unupped so I get 1,700
by the end of each day so that when I get the False God prediction in the morning I can import the relevant anti-deck and, if the deck isn't completely upped I can up a card and if it is completely upped, then I can up a card in any deck I might be building.