Does R&D have any plans to harmonize the names and rules text of tokens, similar to what happened to creature types in Llorwyn? For instance, Thopter artifact creature tokens are usually 1/1 fliers, but Leonardo da Vinci makes 0/2 flying Thopters. So the name "thopter token" doesn't uniquely tell you what the rules text is. Likewise, there are 2/2 Knights with firs strike, 2/2 Knights with trample and haste, 1/1 colorless Spirits, 1/1 white Spirits, and many more examples.

We do within any one set, but we allow variance between sets.

Was there concern about putting both a 0/0 thopter and a 1/1 thopter in the same set? It feels like it could lead to some confusion

Usually when something like this happens, one is the commonly used one and one is the by-product of a small (often one) number of high rarity cards.

Hey Mark, first time asking for Birthday Trivia. Saheeli is my favorite walker so maybe something about her or Kaladesh, or Thopters, something Saheeli-adjacent is cool too. Thank you for being awesome and have a great day.

Originally, Chandra was going to be the face of Kaladesh, but we realized she made more sense for Aether Revolt, so we designed a new planeswalker. We wanted to play up the invention theme, so we made a character that was an amazing inventor, Saheeli.Happy Birthday!

In the latest Odds and Ends, it mentions that artifact sacrificing isn't in blue, both in the color pie nor in the themes of the set. I definitely understand the set themes, as it wouldn't fit in any of the archetypes, but the color pie feels odd. Even in BRO, it got Splitting the Powerstone, and has gotten a lot of other effects like this, such as Clan Crafter, Anchor to Reality or Sai, Master Thopterist. Is this not in blue's pie anymore?

Nope.

Would you ever put a reprint of a regular Magic card in a Universes Beyond set? For example, Ornithopter would be a perfect fit for Dune.

If the name fits, it’s possible.

You said that treasures are deciduous, not evergreen. I believe the same applies for other standard tokens like food and thopters.Are there any standard tokens that are evergreen, not deciduous?

No.

Are acorn (formerly silver) cards able to be errata’d? I was looking at some old favorites and feel it’s now appropriate to allow Thopter Pie Network to allow the thopters to pay two, tap and sac for 3 life.

We have errataed old Un-cards, but what you’re asking for is functional errata which we don’t do very often.

How much design space is there for Zero cost creatures like ornithopter, and kobolds? Are they problematic?

It’s limited. There’s not a lot of options without repeating yourself. There’s also play design concerns if you have too many in any one environment.

How does R&D say hybrid costs when speaking mana costs? Especially the weirder ones like the Mutate ability on the Apexes from Ikoria and things like Thopter Foundry from Alara? What about twobrid like Beseech the Queen and Reaper King?

Let’s say a cost is 2(b/r), we’d say “two hybrid - black/red”. If a card was 2(2/w), we’d say “two hybrid - two/white”’

While I like Mutate mechanically, I find the flavor of mutate to be fascinatingly strange. In Ikoria it is strange enough when a giant moth turns into a Cat Nightmare Dinosaur, but using creature types outside of Ikoria you can have things like a faerie, a spirit, a thopter, a wall, or Sarkhan turning into a Cat Nightmare Dinosaur. Was this considered when developing mutate?

It’s what we in R&D calls the “elephant in the boots problem”. With 20,000+ cards we can make the flavor work some of the time, but there are just going to be cards that want to be open-ended mechanically that result in weird flavor combinations. We just accept that as part of the nature of a trading card game.