1. Myth: One day Zoro will get a Seastone sword.
Fact: When Zoro lost a sword in Enies Lobby, this was one of the most common speculations. Obviously, Zoro would need a replacement and many fans wanted him to replace his lost sword with a Seastone one. Generally, it had been a fairly quiet speculation before then as at the time there was no indication Zoro would ever lose any of his three swords. At this point in time, there is also no further indication that Zoro will lose any more of his swords (considering the fact that one of the swords is considered indestructible). Regardless, this speculation crops up often enough in fan discussions.
2. Myth: Zoro will own all three of the cursed swords Shodai Kitetsu, Nidai Kitetsu and Sandai Kitetsu.
Fact: Much in the same way the Seastone Sword theory sprung out of Zoro losing Yubashiri, likewise did this. Generally, it was not thought that Zoro would ever lose one of his swords. It became another popular theory that one day Zoro would obtain all three generations of the Kitetsu swords. This is most due to the fact their names were already known to the fans prior to Shusui being shown in the storyline and many wanted Zoro to use all three cursed swords as testament to his power. One problem with this myth is that in order to have Zoro have all three Kitetsu swords, all of his would have to be broken/lost etc. That would mean Wadō Ichimonji, Zoro’s most prized sword would have to get destroyed, unless of course that they were all owned at different times.
A variant on this myth is that Zoro will ultimately swap to the other Kitetsu swords in series after losing his Sandai Kitetsu, but there is no more evidence for this than there is for the original theory.