Min/max with Option[T] for possibly empty Seq?

seq.reduceOption(_ min _)

does what you want?

Edit: Here’s an example incorporating your _.something:

case class Foo(a: Int, b: Int)
val seq = Seq(Foo(1,1),Foo(2,0),Foo(0,3))
val ord = Ordering.by((_: Foo).b)
seq.reduceOption(ord.min)  //Option[Foo] = Some(Foo(2,0))

or, as generic method:

def minOptionBy[A, B: Ordering](seq: Seq[A])(f: A => B) = 
  seq reduceOption Ordering.by(f).min

which you could invoke with minOptionBy(seq)(_.something)