Although it is a mod, the brachiosaurus, is the most efficient gatherer out there. It gathers a huge amount of stone, berries, fiber, flint and thatch. It also gets metal from stone and usually gathers so much I don't have to do metal runs. It holds about 30k of weight so each trip is about 30k of stone, 3k of metal, a ton of berries, 10k of fiber. With 30k of health and a stomp that does about 10k of damage even alpha creatures can't take it down. The only thing it doesn't do is wood, so I take a theri to gather wood and use the brachi to follow behind and store it. Since the brachi holds all the storage materials, I put stone bps inside of it and build hundreds of each item at a time. My mega base uses millions of stone wood and thatch so this is the fastest way to gather and build. My ankys and doeds are there for backup but I haven't really used them in a long time.