Can Spike, Tournament Grinder tutor for cards outside of your Sideboard at Launch Night's Draft?
You are able to to get cards outside of your sideboard using Spike's ability in both limited and constructed.

This is adressed by Mark Rosewater (The person in charge of silver bordered rulings) on his tumblr Blogatog.


  bolas-our-lord-and-savior asked: In un limited/constructed spike can get cards not in your sideboard right?
  
  MR:Yes.


Source.



Special note for Commander/EDH play:

With the announcement that Silver-boarded cards will be legal in Commander/EDH until January 15 2018, it should be mentioned that Spike will not work without prior agreement from your play group (as confirmed by Mark Rosewater). This is because Commander already has an established rules for cards that refer to cards outside the game.


  13. Abilities which refer to other cards owned outside the game (Wishes, Spawnsire, Research, Ring of Ma'ruf) do not function in Commander without prior agreement on their scope from the playgroup.


The common way that this is resolved is with the use of a Wishboard.