Actually there are 14 cards with double or triple visible spaces.
Remark: 1 card has two double spaces!
Proof: (copy-paste from gamefiles version 1.0.0.5834(latest))
*Space is marked with "_" for visibility!
Class
Card Name
Card Text
Spaces
Visible in game
Neutral
Ragnaros
Can't Attack.__At the end of your turn, deal 8 damage to a random enemy.
2
Yes
Neutral
Ysera - Nightmare
Give a minion +5/+5.__At the start of your next turn, destroy it.
2
No-new line
Druid
Starfire
Deal $5 damage.__Draw a card.
2
Yes
Hunter
Kill Command
Deal $3 damage.__If you have a Beast, deal $5 damage instead.
2
Yes
Paladin
Blessing of Wisdom
Choose a minion.__Whenever it attacks, draw a card.
2
No-new line
Paladin
Hammer of Wrath
Deal $3 damage.__Draw a card.
2
Yes
Priest
Holy Fire
Deal $5 damage.__Restore #5 Health to your hero.
2
No-new line
Priest
Holy Nova
Deal $2 damage to all enemies.__Restore #2 Health to all__friendly characters.
2 + 2
Yes-both
Warlock
Bane of Doom
Deal $2 damage to a character.__If that kills it, summon a random Demon.
2
Yes
Warlock
Corruption
Choose an enemy minion.___At the start of your turn, destroy it.
3
Yes
Warlock
Demonfire
Deal $2 damage to a minion.___If it’s a friendly Demon, give it +2/+2 instead.
3
Yes
Warrior
Brawl
Destroy all minions except one.__(chosen randomly)
2
Yes
Warrior
Commanding Shout
Your minions can't be reduced below 1 Health this turn.__Draw a card.
2
Yes
Warrior
Grommash
Charge.__Enrage: +6 Attack
2
Yes
Warrior
Mortal Strike
Deal $4 damage.__If you have 12 or less Health, deal $6 instead.
2
Yes
Warrior
Shield Block
Gain 5 Armor.__Draw a card.
2
Yes
Warrior
Slam
Deal $2 damage to a minion.__If it survives, draw a card.
2
Yes
Warrior
Upgrade!
If you have a weapon, give it +1/+1.__Otherwise equip a 1/3 weapon.
2
No-new line
Edit: Table & more research.
P.S. For science!
This is rad. :) I'll take a look and see if I can make things more consistent.
No, it is absolutely not. It is a habit on par with heroin use that any typographer will accost you endlessly for. It is completely, inarguably wrong if you are using a proportional face, and still wrong with most mono-space faces. You may as well be using exclusively capital letters set in comic sans, it's an easier way to achieve the same effect on the page's readability.
Ben Brode
Aldor Peacekeeper has your back.
Ben Brode
This is rad. :) I'll take a look and see if I can make things more consistent.
Ben Brode
Interesting article on the subject: http://www.heracliteanriver.com/?p=324