Is there a shorthand for {|x| foo x}?

You can reference the method to pass as a proc with method:

list.map(&method(:foo))

Maybe not the shortcut you're looking for, as it's limited to work with methods that expect only one argument and reduces readability.

Adding a bit more context to the answer supplied by Sebastian Palma.

method(:foo)

Returns the method foo of the current instance (self). You can also use this in combination with other instances:

(1..10).map(&5.method(:+))
#=> [6, 7, 8, 9, 10, 11, 12, 13, 14, 15]

Here 5.method(:+) returns the + method for the instance 5.