One of them is Twiddling Time Vault for a free turn. It was just obvious that that's how it worked. We accepted umpteen errattas to fix it, but when Wizards decided that they don't do Power Level Erratta anymore, we can now twiddle Time Vault. I mean, it just can't be unseen.
Also back in the day, Wizards had demons. Dungeons and Dragons had demons. They changed it to some name I can't recall
(Horrors - Godder), but everyone knew they were demons. TSR (publishers of AD&D at the time) tried to get some controversial stuff re-branded to placate certain religious groups. Or that's what they told us. I dunno if AD&D had demons now
(it does - Godder), but Wizards did a similar thing back in '94ish.
Unholy Strength.

I've seen tidbit after tidbit about this pentagram thing, and how Wizards was playing it safe by removing the pentagram "just in case".
But once you see it, it can't be unseen.
The pentagram was STUPIDLY drawn. Imagine a CIRCLE (with a star in it). Now look at the "CIRCLE" of Unholy Strenth's pentagram.
If you had to draw a "circle" in Geometry Class (or say, in a 4th grade math class homework problem : "Draw a circle. Make it look circular") and you drew they above "circle", you would be a Fail. Doug Shuler was a fail in this pic. Actually, a lot of his pics of "people" were kinda bland, but I digress.
Can you unsee that awefully drawn pentagram now that you've seen it?
Why is Wizards/Hasbro/MTG.com covering this up?
Cite a source? Sure, smartass... :
http://www.wizards.com/Magic/Magazine/Article.aspx?x=mtg/daily/mm/94