Sapayoa has modestly easy chances in Panama in the way to Darien or the Choco in Northern Ecuador, not really a bird worth making a trip for if you've already birded the region a lot but if you want all of the bird families, I think it's one of the easier bird families to get along with Wrenthrush in Costa Rica from the point of view of an American birder in these years.Sapayoa
Dapple-throat and Allies
I've been to PNG twice and still miss Ifrita. Berryhunter and the melampittas were split after we were there, or we would have insisted. (We did insist on berrypeckers.)
I've been to Bhutan twice (lots of fun, no endemic families), again, before they split the Elachura, so it was not on our wishlist. The easiest would probably be to go to Costa Rica and get Wrenthrush.
All of these except for the Sapayoa are recent splits - recent for me, that is. And all of them are in places we've been before, so it's that much less fun to go there again just because of a split.
We started this game after Madagascar, when we discovered we were way over 200, and the end was in reach. In fifteen years, I've added 24 families, plus some armchair ticks, like splitting Sylviidae. But we can't manage it any more, and we've lost not one, but probably two years because of the virus.