Selesnya Loft Gardens

If an effect would create one or more tokens, it creates twice that many of those tokens instead.
If an effect would put one or more counters on a permanent, it puts twice that many of those counters on that permanent instead.
Whenever chaos ensues, until end of turn, whenever you tap a land for mana, add one mana of any type that land produced.

March of the Machine Commander

Planechase Anthology Planes

If an effect would put one or more tokens onto the battlefield, it puts twice that many of those tokens onto the battlefield instead.
If an effect would place one or more counters on a permanent, it places twice that many of those counters on that permanent instead.
Whenever you roll {Chaos}, until end of turn, whenever you tap a land for mana, add one mana to your mana pool of any type that land produced.

Planechase 2012 Planes

If an effect would put one or more tokens onto the battlefield, it puts twice that many of those tokens onto the battlefield instead.
If an effect would place one or more counters on a permanent, it places twice that many of those counters on that permanent instead.
Whenever you roll chaos, until end of turn, whenever you tap a land for mana, add one mana to your mana pool of any type that land produced.

Adding loyalty counters to a planeswalker in order to activate a loyalty ability isn't an effect, so those counters are not doubled.

Any -1/-1 counters that are placed on a creature because of wither or infect are also not doubled.

Effects that place a counter on a permanent include that permanent entering. For example, a creature that normally enters with one or more +1/+1 counters will enter that many +1/+1 counters on it. A planeswalker will enter with twice its starting loyalty counters.

The chaos ability is cumulative. For example, if you roll {CHAOS} twice in a turn, tapping a land for mana will cause two mana abilities to trigger.