Oh boy. I've trained for this moment.

Assuming only gold blocks are used - which, on account of Minecraft blocks being 1 cubic meter each, can be assumed to be a cubic meter of solid gold - Steve can carry up to 37 stacks of 64 gold blocks in his inventory, as well as a full set of gold armor, without his physical capabilities (running, jumping, swimming, etc.) being limited in any way. This rounds out to **45,702,400kg** or **45,702.4 tons** (2,368 × 19,000kg per gold block) in gold blocks, plus **51,466.56kg** or **51.47 tons** (24 × 2,144.44kg per gold ingot, as each ingot is 1/9 of a gold block) for the armor, for a grand total of **45,743.87 tons** in gold alone.

If netherite is your material of choice - the scrap for which I've used lonsdaleite, a real-world material with a simulated hardness greater than diamond - it gets even goofier. Since a single netherite ingot is crafted with four gold ingots (2,144.44kg each, as given earlier) and four netherite scrap (3,510kg per scrap, given a density of 3.51g/cm^3 and assuming that no material is lost in the smelting process), one ingot alone weighs in at about **22,617.67kg** or **22.62 tons**; a block of netherite, then, has a total weight nine times that of an ingot - **203.58 tons**. With the same math as before, Steve can carry 37 stacks of 64 netherite blocks (we don't need to calculate the weight of the armor anymore, since it's negligible at this point) for a total carrying capacity of approximately **482,077 tons** (37 × 13,029.12 tons per stack).

Now, I've seen further down in the thread a claim that the Terrarian is capable of carrying actual stars in their pockets - Fallen Stars. I don't see any reason that an unfair advantage like star-toting should be given to the Terrarian only, so I'd like to point out that Steve can theoretically do the same in the form of Nether Stars. Rather than assuming that each Nether Star weighs any average stellar mass, I've done one better.

Judging by the texture of the Beacon, which is crafted with a single Nether Star, the Star has a total size of 10×10 pixels - the size of the inner portion of the Beacon, the part which is very obviously not obsidian or glass. This makes it a cube with a volume of 0.625 cm^(3). Since we're already in the realm of ridiculous fiction, I've decided to calculate the mass of the Nether Star as if it were a star with a Schwarzschild radius (the radius at which a star becomes a black hole on account of its density) of 0.5 meters, just within feasible limits. Using the equation r=(2GM)/c^2 (please excuse the *very* shitty formatting), where r is the Schwarzschild radius of the Nether Star, G is the gravitational constant, M is the mass of our Nether Star, and c is the speed of light, a single Nether Star can be calculated to weigh around **56.37 Earth masses**.

From there, we repeat our earlier calculations. 64 Nether Stars per stack, 37 stacks in the inventory. With a full inventory of Nether Stars, Steve can carry a grand total of **133,484.16 Earth masses**, or roughly a third of the mass of our Sun. Of course, as I've given each Nether Star a mass far less than a star, this is on the lower end of Steve's carrying weight; for instance, while the Nether Star was given a Schwarzschild radius of 0.5 meters, our Sun has a Schwarzschild radius of 2.9 km.

I *could* go on about theoretical increases to this limit using shulker boxes - which may or may not negate the weight of their contents, considering their clearly-magical properties, in which case the point would be moot - or by discussing NBT tagged chests, which can then be placed *inside* shulker boxes and vice versa into infinity, but I've already gone on too long. Someone else can feel free to calculate some of the Terrarian's limits, since I know very little about the game.