I haven't really tried super in-depth each item, but I've found that Ancient Coin (which I still call the Shurelya line...old habits die hard I suppose) is the most reliable, with nice health and mana regen and the active on Talisman(final build) is always useful for the whole team.
Frost fang line is ok on supports that have something attached to their autos (Sona or Lulu come to mind) and once you upgrade it, you get money for spells too. I just don't think it's as much at it seems...the gold you get from harass only goes off every 10 seconds, and in lane phase that can be a very long time. If you kill a minion it shuts off as well. You also don't get a ton of AP from it, you're probably better off buying Coin, then a better AP item later. And while the active on Frost Queen's whatever is ok, it just can't compare to Shurelya's.
TL;DR Frost Fang line is not terrible, but the other gold items are just better, more reliable options with better actives. Since you can only choose one, I tend to favor Ancient Coin on ranged supports that aren't Thresh.