The Coldsnap land 'Dark Depths' produces a Marit Lage token.
No, unless they have haste.
The artifact creature 'Pentavus' can remove its +1/+1 counters to create 1/1 flying Pentavite tokens.
Single cards that represent a creature (token) there are currently 199 that I am aware of.
Mercy Killing targets one creature, and the creature's controller sacrifices it when Mercy Killing resolves. That player then gets some Elf tokens, as outlined on the rest of the card.
An Ooze token is a creature that can be created. The token card is the representation of that creature.
A giant deck is a deck consisting of the creature type giant.
'Casting a creature spell' means to pay the mana cost and put the creature spell on the stack. If this is allowed to resolve, then the creature enters the Battlefield.
Whenever a creature with lifelink deals damage, (combat or otherwise) to a creature or player, you gain that much life.
If creature has Reach, it can block flying creatures without having to have flying itself.
No. You cannot kill the creature that is sacrificed in reponse to it being sacrificed as it is already gone.
Tokens go to whichever zone, and then immediately cease to exist. So while cards which say "when a creature goes to the graveyard" will trigger when tokens go there, the tokens themselves do not stay in the graveyard, they just disappear. So no, they are not there for other abilities to bring back to the battlefield.
If a creature has Intimidate, when it attacks, it can only be blocked by creatures that share a colour with it, or artifact creatures.