If the exact criterion for inclusion is "set that was once standard legal", WAR is the 100th because Chronicles was at its time a Type II legal set. It wasn't considered an expansion (the official designation was an extension of 4th edition), but it is a set. 18 core + 81 expansions + Chronicles = 100.

Interesting. Let me look into it.

One thing that really bothers me about the reserve list is why, if it's a good policy, does Wizards not update it? Why is it okay to protect older players' collections from losing value, but not my newer cards? What makes Modern Masters acceptable, but not Chronicles? It seems to be a double standard.

The Reserved List is a promise we’re living up to, but not one we want to recreate.

Hey Mark, it's my birthday today! Do you have any Magic Trivia about how the Chronicles of Narnia might have influenced any part of the game?

I don’t know if any concrete connection, but that doesn’t mean there isn’t any. Richard is well read and loves fantasy, so there’s a strong chance it had an influence, just not one I’m aware of.Happy Birthday!

What would the consequences be of printing Modern Masters 3 at an unlimited quantity?

I suggest reading some articles about what happened with Chronicles and Fourth Edition.

On Phyrexian Negator and the Reserve List, Chronicles burned me and I quit the game. Today, I think it would be healthy to have some loopholes. I have less respect for WotC sticking to a policy that benefits far fewer people today than it used to.

We’ve done research on opinions on the Reserved List. The pro-Reserved List crowd stays mostly silent on social media, but it’s a much bigger number than I assume most of you guess it is.

Why was Tarmogoyf, Bob and Vendilion Clique raised to mythic rarity in the first Modern Masters? Were you just scared of experiencing a Chronicles 2.0? In the past you have said that complexity and balancing for limited formats define the rarity of a card. Are there going to be any changes to the rarity of cards that are going to be in Modern Masters 2015?

I said those two were the major factors. They are not the only ones. The tricky balancing act of Modern Masters products is getting the cards into the hands of players who don’t own them without destroying the value of the cards for players who do own them.

In five years when you do the silver anniversary of Magic, perhaps you can amend your "20 things that Almost Killed Magic" to include 5 things that actually almost did like: overprinting Fallen Empires, following up the Chronicles debacle with a set like Homelands, the Over-powered-ness of Urza's block, following up Urza's block with the utter crappiness of Masques block, and Time Spiral's block of overcomplicated mess? I think each of those put the game in more danger than Nalathni Dragon.

The article was more about controversies than things that were actually in danger of killing the game. I just chose an attention-grabbing headline.

Don't you think modern masters' print run was too low? Can't you make another print run to make it more accessible?

My best answer to this question is to study Magic history and see how Chronicles made that mistake and all the bad things that happened as a result.

As always, when the issue of who supports the Reserved List comes up, feel free to dime me out. I support the Reserved List wholeheartedly. Ask the folks who want to abolish the Reserved List what they were playing when Chronicles was released.

Most people don’t speak up when they know there is a vocal majority so thanks for demonstrating that Reserved List supporters do exist.

Sorry if this as been addressed before. Some multicolored cards follow the order of WUBRG in their mana cost. WUBRG cards cost WUBRG, UB cards are UB, etc. But other cards like WG cards cost GW and WR cards cost RW. Why is that?

Here is Del Laugel, Magic’s lead editor answering this question in a 2002 Ask Wizards question: Q: "Why do mana symbols seem out of order on various gold cards? Some cards requiring green, white, and blue mana, like Treva’s Charm (), have it in that order. Some cards, like Phelddagrif(), go white, blue, and then green. Rubinia Soulsinger () goes blue, white, green. Shouldn’t there be more organization?“
– Cid Silhouette, Boston, MA A: From Del Laugel, Magic technical editor:
"As you’ve noticed, three different systems have been used in the past to order mana symbols on cards. One system always put the colors in the order white-blue-black-red-green, and that ordering was used for Ice Age, Tempest, and Chronicles. Another goes clockwise around the "pentagon of colors." Mirage block used that ordering, and we’ve been following it consistently since Stronghold. And then there’s the Legends system, which involved throwing mana symbols into a hat and then pulling them out at random. "Our current (and final!) system for ordering mana symbols is pretty simple. If you look at the back of a Magic card, you’ll see the pentagon of colors. Going clockwise, the colors are white, blue, black, red, green, white, blue, black … . To order a pair of mana symbols, find them in that list, and then put them in whichever order puts the fewest colors between them. For example, white/red has two colors in the middle (blue and black), but red/white has only one (green). That’s why Goblin Legionnaire’s mana cost is . "Then came the Apocalypse 'wedge’ cards. Our system breaks down when you’re trying to order two friendly colors and their common enemy, and Apocalypse has five rares with mana costs that fall into that category. For Lightning Angel’s mana cost,  and  are equally valid options. In the end, I decided to put the enemy color pair first. ”(Yes, I know that the Apocalypse split cards all violate the color order. It was decided that those five cards would be easier to name that way.)“