Looking at a Marq Athlete.
The accessory bands look different colours in the shop. I suspect this is lighting thing. For example the Avaitor band looks a little gold but on the Athelete part of the site it's shown with that band and it matches.
I like this band: https://buy.garmin.com/en-AU/AU/p/610842/pn/010-12738-20:
QuickFit® 22 Watch Straps
Hybrid Metal Bracelet
PART NUMBER 010-12738-20
It appears in the MARQ accessories and looks to be a plain titanium version of the carbon Driver band. It looks almost made for the Athelete as it has black silicon which would match the bezel.
My only concern was that it looks a little more grey than the titanium case, but I'm guessing it's not. Has anyone seen it? Worst case I order it from Garmin and return it within the 30days if it doesn't match. I don't like the clasp on the Avaitor but I can probably fall back to that if it doesn't match.