I know 21 commander damage got decided on due to the original cycle of Elder Dragons having 7 power and you getting hit three times equaled 21 but the book quote is just so fitting for our format
If an opponent tries to destroy a creature with all of your Auras and Equipment attached to it, for two mana you can move all of them to another creature, or spread them between several creatures
Playing a Commander who benefits your opponents as much as you also makes it less likely that card becomes a target
Dimir Excruciator A top tier mill deck is a surprising thing to see, but Dimir Excruciator took home the trophy during Pro Tour Lorwyn Eclipsed
Opponents are going to want to stop the Korvold party whenever they can, and Sylvan Safekeeper can keep any sort of pinpoint removal away
Technically, both cards can do the same theft effect with a small difference: The creature half can exile a card from an opponent's hand, and they pay its mana value to have Valki transform into it