Hello Mr Rosewater,
Un-rules question for you:Modular Monstrosity has the ability, "Whenever an opponent casts a spell, you have five seconds to choose a keyword you haven't chosen for a card named Modular Monstrosity today that's been printed on a creature card."There is also a ruling that reads, "If the keyword has a modifier, such as a mana cost or a number, you must choose a modifier that’s been printed."
My question is, can you choose a keyword that has been printed on a creature with a modifier that's only been printed on a noncreature card. Cumulative Upkeep has appeared on many creatures so is a valid keyword. Can I name "Cumulative Upkeep-Add {R}" which has only been seen on the noncreature Braids of Fire?
Thank you in advance

You have to choose a mechanic and a modifier that’s appeared on a creature.

Regarding the hypothetical Ward costs that give opponents an upside instead of directly costing you anything, there's at least one card which does that repeatedly: Wall of Shards has an opponent of your choice gain life as a cumulative upkeep cost. This demonstrates that the game already treats benefiting your opponents as a cost.

Just because a card was printed once that does something doesn’t mean all problems with that thing were solved. Wards have to be costs and another player doing something isn’t a cost.

Hello Mark, I have an un-rules question. Saw the Giant Fan came up recently and I've been considering it for a Cumulative Upkeep themed deck. Do counters referenced by keywords but not explicitly mentioned in the text count for Giant Fan? If I were to move a Velocity counter from Tornado onto a Herald of Leshrac, would that counter be turned into an age counter because Cumulative Upkeep refers to age counts implicitly, or would it be turned into a +1/+1 counter because the reference to age counter is not in the actual text but only in the comprehensive rules? My understanding from un-sets is that "rules text" usually only refers to the non-italicized oracle text in the text box of a card, but I'm not sure that's correct.

When Unsanctioned came out, we did an Oracle pass on the Un-cards. Giant Fan now cares about cards that “refer to” rather than caring specifically about rules text, so reminder text would matter. We’ve also ruled that if the counter is inherent to the card type, it will also get the counter, so using a Giant Fan to move a counter onto a planeswalker will get you a loyalty counter.

If/when: A new card with Cumulative Upkeep

If. We’ve mostly moved on from cumulative upkeep. The best chance would be a one-of in a Modern Horizons.

I know you don't do cumulative upkeep anymore, but what colors could give all creatures cumulative upkeep?

It depends on the cost. For mana, white does the most taxing.

If/when: no-liferate, the opposite of proliferate where you remove counters. You know, for preserving sagas, cheating on cumulative upkeep, foiling your opponent's suspend cards, etc.

If. We don’t want to remove poison counters.

Doesn't Psychic Vortex ("Cumulative Upkeep - Draw a card") mean that "draw a card" can be a cost?

You drawing a card can technically be a cost, but that’s not what ward - draw a card is. It’s your opponent choosing to pay a cost of you drawing a card, which can’t be a cost. You can’t make others take an action as a cost you pay.

Has there ever been consideration to an "Upkeep " keyword, like there is for "Cumulative upkeep "? It seems a bit weird that the latter exists but the former is always fully spelled out as "At the beginning of your upkeep, sacrifice this unless you pay ", even in older sets before the wording was changed from "During your upkeep, pay or bury this".

We use upkeep costs so rarely these days, it isn’t really worth doing.

In theory, could the rules support a lord creature that cared about creatures with Echo or Cumulative Upkeep?

The rules can care about keywords. Right now, it can’t care about ability words.

Is there a possibility of some older mechanics like cumulative upkeep costs ever coming back, even in silver border? It could lead to some interesting effects

Black border can still do cumulative upkeep. It’s not a silver border thing (barring silver border costs/effects).