The most obvious of these factors is the synergy of haste with Saproling Burst, which was known to some as "The Fix." That extra turn almost doubled the strength of the Burst and made it hit for the full 20 damage in only two turns, which would normally mean a kill on turn five, or turn four if backed up by a Blastoderm
Each booster contains Rares and/or Mythics, Traditional Foils, a Borderless basic land, and more
So if you wanted to buy one, now is likely a good time, especially since $59.99 now seems to be the market price at the very least
Non-regular boosters[] Six-card boosters[] Six-card booster packs contain a tips/token card, one land, three commons, one uncommon, and one slot with an equal chance of being rare/mythic, uncommon, or common