A speed run from when you spawn into the world and then have to reach bedrock as quickly as possible can be an interesting run. I've attempted it a couple times and my pb was 1:27 with decent rng. If someone gets really lucky they can honestly sub 1 minute. The basic strategy is getting 3 wood to make a crafting table, wooden pickaxe, wooden shovel, and sticks. Then run to a cave and mine straight down at the lowest point to get 3 cobblestone for a stone pickaxe, and finish the run by mining until you reach bedrock.

It will be really cool if this became a new category and I'm sure many people will optimize to become faster.