People are recommending stone which is easily the worst choice for OP's question for "best resource to gather at the start". Stone is completely worthless before T7 ever since the laborer/journal changes gutted the price of T6 stone. Once you get to T7, stone is actually pretty decent despite prices for Basalt and Marble being lower than they were in the past simply because of how much less contested it is now (particularly plentiful stone nodes in T7 zones). Fiber and Hide are worth significantly more than their counterparts at all tiers. I would personally give Fiber the edge over Hide simply because it is less contested overall and is faster to level due to not having to kill skin mobs.