Prime speaker

[Taysby]

I now have a prime speaker commander deck that wins with lab man and nothing else

What are the most effective draw spells?

[redwolv]

Depends. There are ones that draw quality, ones that go for quantity, and ones that let you dig(draw&discard). There are also enchantments that let you draw/dig extras which could be useful.

Examples in the orders I listed
{Ponder}
{dig through time}
{wheel of fortune}(there is similar stuff in blue)

{Dictate of Kruphix}
{monastery siege}

the draw discard effects would be fastest at getting you to that last card, but once you find lab, you can't discard a whole hand. Self milling can also work well but you risk losing the lab to the mill.

One Other thing is stuff like  {Life's Legacy} with large creatures they are some of the best draw spells in the game. 
Also a large amount of mana into a {Genesis Wave} could really get you there.

[Thefluffymacheen]

 {Jace's Archivist},  {Enter the Infinite}

Also if you're playing green / blue you may as well throw in the  {Illusionist's Bracers} /  {Kiora's Follower} combo or even the infinite loyalty counter combo to help generate infinite mana. If you achieve infinite mana then you basically win seeing as every card draw spell will likely get you another card draw spell.

*EDIT*  {Kruphix, God of Horizons} would also be a good add to help with ramping into larger mana cost card draw spells.

[LinkCelestrial]

{Fruit of the First Tree}, {Skyscribbling} type things. There's that draw 20 ult Jace...

[ELLERfeller]

 {Well of Lost Dreams} would pair well with any form of life gain