In many decks, they end up being the anchor of the strategy, whether thats reanimating creatures, looping spells, or enabling anything from cost reduction to card draw
They are all colorless because Mishras Workshop or Ancient Tomb is just too good and there are enough crazy ramp lands in the older formats to support a deck like that
Creatures with ravenous feature an X casting cost, but they allow you to draw a card when they enter the battlefield if X is 5 or more
In the rare case where the original creature is copying something else when the offspring ability resolves, the token enters as whatever that creature copied, except it's a 1/1
(Mana abilities can't be targeted.) "I see
Some (but not all) triggered delirium abilities use an intervening "if" clause