Cheapest priced copy (Reality Fracture Commander): $0.49 at Card Kingdom, near mint, their price list as of .
Synthetic Destiny 
Instant · Rare · Kaldheim Commander · #44
Exile all creatures you control. At the beginning of the next end step, reveal cards from the top of your library until you reveal that many creature cards, put all creature cards revealed this way onto the battlefield, then shuffle the rest of the revealed cards into your library.
Legal inCommanderLegacyVintage
Not legal inBrawlStandardPioneerModernPauper
3 printings · $0.49 to $0.79 at Card Kingdom
| Set | Number | Rarity | Card Kingdom | Foil |
|---|---|---|---|---|
| Commander 2015 | 15 | Rare | $0.79 | — |
| Reality Fracture Commander | 45 | Rare | $0.49 | — |
| Kaldheim Commander | 44 | Rare | $0.49 | — |
6 rulings from Wizards of the Coast
- 4 November 2015The cards you exile will stay in exile. They're not part of the group you shuffle into your library.
- 4 November 2015If you don't reveal any noncreature cards this way (perhaps because all the creature cards you needed were on top of your library), you still shuffle your library.
- 4 November 2015The creature cards will enter the battlefield simultaneously.
- 4 November 2015Creature tokens you exile this way will count toward the number of creature cards you put onto the battlefield.
- 4 November 2015If you exile your commander as Synthetic Destiny resolves, you may not put it into the command zone until after Synthetic Destiny is finished resolving. It will still count toward the number of creature cards you put onto the battlefield.
- 4 November 2015If the number of creatures you exile is greater than the number of creature cards remaining in your library, you'll wind up revealing your entire library, putting all creature cards revealed that way onto the battlefield, then shuffling your library.