From discussions on goblin artisans.

People had many suggestions for the egyptian-themed set of creatures which could attack or block in an afterlife of some sort. But I think earlier, someone suggested the simpler "Afterlife (you can activate activated abilities of this card from the graveyard)"? Or maybe "only from the graveyard"?

Not being able to attack or block removes the vast majority of the unpleasant complexity. It's still startlingly different to anything that's come before. In fact, more so than ones that return the creature to the battlefield, because they can look a lot more "in the graveyard" when they don't have to be laid out in a pseudo-battlefield.

You have to be able to lay the creatures out so they're obviously different to the rest of the graveyard, but we've done that before with flashback, etc.

It's fairly easy to balance because you can choose what activated abilities to have. But you can have a splashy rare that gives other creatures afterlife.

You can use simple utility abilities. Llanowar Elves or Gideon's Lawmaker would be too strong, as it almost turns Llanowar Elves into Rampant Growth with a body, but a slightly weaker version would probably be ok even if there's not much removal.

There's existing removal "exile target card in a graveyard" etc which can solve these creatures, and this set can have more of it.

I don't like that death doesn't matter much. Maybe it should have a slgihty-worse or slgihty-better ability in the afterlife?