Describe the problem
Since the new Gatherer Update, Sewers of Estark and Windseeker Centaur no longer have any printings listed on Gatherer. There used to be a miscellaneous promos set which included these two printings, but that set is no longer present and with that the only printings of these cards have disappeared as well. Worth noting that other 3 Harperprism prints and Nalathni Dragon's DragonCon print disappeared with that set's disappearance as well, but those have other printings that Gatherer covers.
For the closest I can get to a relevant link, here is the gatherer page for Arena, which used to have the Harperprism printing but no longer does with the Gatherer update: https://gatherer.wizards.com/MB2/en-us/239/arena
Describe the problem
Since the new Gatherer Update, Sewers of Estark and Windseeker Centaur no longer have any printings listed on Gatherer. There used to be a miscellaneous promos set which included these two printings, but that set is no longer present and with that the only printings of these cards have disappeared as well. Worth noting that other 3 Harperprism prints and Nalathni Dragon's DragonCon print disappeared with that set's disappearance as well, but those have other printings that Gatherer covers.
For the closest I can get to a relevant link, here is the gatherer page for Arena, which used to have the Harperprism printing but no longer does with the Gatherer update: https://gatherer.wizards.com/MB2/en-us/239/arena