Do not be so caught up in keeping track of time that you forget to make use of it.

Perpetual Timepiece

{T}: Mill two cards.
{2}, Exile this artifact: Shuffle any number of target cards from your graveyard into your library.

Outlaws of Thunder Junction Commander

{T}: Mill two cards.
{2}, Exile Perpetual Timepiece: Shuffle any number of target cards from your graveyard into your library.

The List

Kaladesh

{T}: Put the top two cards of your library into your graveyard.
{2}, Exile Perpetual Timepiece: Shuffle any number of target cards from your graveyard into your library.

You can activate Perpetual Timepiece's second ability with no targets just to shuffle your library. If you choose any targets and they all become illegal targets, the ability won't resolve and you won't shuffle your library.