The 18-35 Nikkor is hard to beat as a travel WA zoom, but the 16-35 feels more solid in use and is weather sealed. The Tamrons, both the current 17-35 and the 15-30 are nice lenses if your raw converter can correct the distortion at the widest focal lengths.
The Tamron 15-30 needs an expensive filter holder and even more expensive 150 mm filters, the others have a 77 mm filter thread.
The current Sigma Art WA zooms get good reviews, but I haven't used them.
The Tokina 16-28 has softish edges and lots of CA, even if the Opera version is better than the earlier ones.
If I was looking for a travel wide angle zoom, I would go with one of the Nikkors over the third-party offerings. The 18-35 balances well on a D750 without a grip, but it feels less well-built than the 16-35 and isn't as nice on a gripped body. Less mass and cheaper vs better feel, your choice.
If the mass and bulk doesn't make you leave it at home, a used 14-24 or a new G2 Tamron 15-30 might be worth considering.