General Sideboarding
In general decks have two ways to deal with infect, there is either lots of removal or lots of blockers. If they have lots of blockers the trample provided by Rancor and Predator's Strike is useful but if they are on the removal plan then trample is not what you need. The flexible cards are Mutagenic Growth, Predator's Strike, Rancor, and Rot Wolf.

Fog: for fast aggro-combo decks like Infect and Eye Candy taking out Predator's Strike
Giant Growth: a replacement pump for when Mutagenic Growth or Predator's Strike come out
Hornet Sting: against white decks with Standard Bearer also the mirror
Nature's Claim: artifact and enchantment decks
Ranger's Guile: more protection against targeted removal
Corpse Cur: against hard removal in Red/Black decks, take out the Rot Wolfs for these

Delver Fae
-3 Predator's Strike, -3 Mutagenic Growth | +3 Hornet Sting, +3 Ranger's Guile
Turn one Glistener Elf is very difficult for them to deal with. If they show you Piracy Charm keep the Mutagenic Growths and take out Rancor.

MBC
-2 Mutagenic Growth | +2 Corpse Cur

Burn
-4 Mutagenic Growth, -2 Rot Wolf | +1 Giant Growth, +3 Ranger's Guile, +2 Corpse Cur

Kuldotha Boros
-3 Predator's Strike, -3 Phytoburst | +2 Nature's Claim, +2 Ranger's Guile, +2 Corpse Cur

RUG Tron
-3 Mutagenic Growth | +3 Nature's Claim

Dimir Teachings
-3 Predator's Strike, -2 Rot Wolf | +3 Ranger's Guile, +2 Corpse Cur

Eye Candy
-3 Predator's Strike | +2 Fog, +1 Giant Growth

Counterburn
- 3 Predator's Strike, -2 Rancor | + 3 Ranger's Guile, + 2 Corpse Cur
Keep mana and protection up to dodge burn.

Affinity
-4 Mutagenic Growth, -3 Phytoburst | +4 Nature's Claim, +3 Ranger's Guile

White Warriors
-4 Mutagenic Growth, -2 Groundswell | +3 Hornet Sting, +3 Nature's Claim

Goblins
-1 Predator's Strike | +1 Giant Growth

Elf Bomb
-4 Mutagenic Growth, -1 Groundswell | +3 Hornet Sting, +2 Nature's Claim

Infect
-3 Predator's Strike, -3 Phytoburst | +2 Fog, +1 Giant Growth, +3 Hornet Sting
Luck dependent

Domain Zoo
-1 Predator's Strike | +1 Giant Growth

RDW
-4 Mutagenic Growth, -1 Rancor | +3 Ranger's Guile, +2 Corpse Cur

Hexproof Auras
-3 Mutagenic Growth | +3 Hornet Sting
Hornet Sting is to kill Standard Bearer, alternatively you can use Apostle's Blessing on it and go for a one-shot kill. If you think they don't have Standard Bearer or aren't a particularly competent player, you can get away without sideboarding.

MUC
-1 Mutagenic Growth | +1 Giant Growth

Winter Zoo
No sideboarding

Stompy
-1 Phytoburst  | +1 Giant Growth