Elrond and Numenor
There’s no mention of Elrond ever visiting Numenor, even while Elros was still alive, and I don’t think it ever happened. Elrond and Elros’s parting was a very painful one, and I think it’s likely that they decided that dragging the process out (and making Elrond watch his brother grow old) would be too much.
If you look at LOTR, the same thing happens with Elrond and Arwen. After Arwen marries Aragorn, they both accompany the hobbits and Elrond west towards Eriador. While stopping at Edoras, Arwen and Elrond take a walk in the mountains and say a long goodbye. Then, though Aragorn travels with the group a bit longer, Arwen stays behind. And, during the two more years that Elrond lives in Middle Earth, he and his daughter never see each other. It seems that Elrond was a fan of clean breaks, and you can’t really blame him.
For the record, there’s no mention of any of the elves of Middle Earth visiting Numenor, though some elves from Tol Eressea did visit the Numenoreans (and the Numenoreans visited Middle Earth, of course.)
SOURCE: The Silmarillion, LOTR, LOTR Appendices