For bikepacking trips with the Checkpoint gravel bike, I wanted to optimize for all sorts of different terrains I could encounter while bikepacking, and my local bike shop recommended the WTB Riddler 700x45c (tubeless) for that purpose. I thought the smoother center line would reduce rolling resistance on tarmac, but the wider profile and knobs on the sides offer decent traction on dirt and gravel roads. While the front tire lasted for close to 5000km, the rear tire had to be replaced about halfway through my ride through New Zealand.
At that point, I switched to Vittoria Terreno Dry 38c (tubeless). These were praised by a bike store in New Zealand because of the addition of graphene improving durability and performance. I used them in the rear and had a great experience with them for the rest of New Zealand, my ride in Western Australia, and in Vietnam.
Lacking other options, I swapped the Vittoria for a Schwalbe G-One Allround in Taiwan, again for the rear tire. The small knobs provided decent grip on various surfaces, however after putting them to the test in Japan, Norway, Switzerland, and Austria, the knobs along the center were eventually worn down.
The Bontrager GR1 Team Issue (tubeless) provided a similar profile to the Schwalbe and used it for trips in Italy and Oman.
Halfway through my trip in South Africa, I encountered some rough and sharp gravel climbing up the switchbacks to Rooibergpass, which the Bontrager tire did not handle too well. I switched to Panaracer GravelKing SK Plus, 700×43 (tubeless), the GravelKing being one of the most popular tires in the gravel riding community. The Panaracer, so far, seems to possess an almost ideal combination of versatility and durability for medium to long bikepacking adventures.
Panaracer GravelKing SK+, 700×43 (tubeless)
WTB Riddler 700x45c (tubeless)
Vittoria Terreno Dry 38c (tubeless)
Schwalbe G-One Allround
Bontrager GR1 Team Issue (tubeless)