In the large box is a note saying 'it's in the medium box', in the medium one is one saying 'it's in the small box' and in the small box the note said 'Oops smallpox'.

Bank account report showing millions of dollars in my US accounts, taxes pre-paid.

Cannabis oil.

A receipt for a self-driving, self-sustaining RV with zero emissions.

Large-a snake, medium-a lizard, small-a tarantula. But I would be suspicious of the postman delivering to my door because I can’t get mail here.

I hope she has breathing holes in there

I will return them back to sender. Nothing I want is shipped in a box.

In the big box, there is my happy and successful future as a writer living in New Zealand, in the medium box is my happy family and friends, and in the small box is a gold and meteorite wedding ring to remind me that all things are temporary in their permanency and that a star had to die in a supernova for me to exist 4.5 billion years later.

I'll never know, the damn door bandit got to them first ??????

(sobbing) I don’t know!

• small: the credentials to a Swiss bank account containing billions of dollars

• medium: the button contraption from The Box that kills a stranger, but modified to instead kill one of my enemies at random without a trace each time I press the button

• large: a TARDIS

This is going to sound so melodramatic but I'm going to answer this sensibly, just for a change.

So long as one of the boxes has my eldest daughter somewhere in it, I haven't spoken to her in person for nearly 6 years (Long story) I wouldn't care about the other two so would give them away, probably to my daughters

Solid cash money in large bills. All of them.

---to fit the criteria of this question, the items have to be tangible and things that a postman could physically carry and fit into his little white Grumman LLV

Large -- a mint pair of MCM Deena lamps with original shades that I don't already have
Medium -- a new laptop
Small -- Round-trip Tickets to England in December for 3 weeks to see my mum and sisters

Large: a Nord stage 3 electric piano
Medium: a 3 year supply of cannabis, hash, vape oils and insanely strong gummies. (make that a 10 year supply, 7 of it is pressed into the packing material for the keyboard)
Small: a new iphone loaded with unlimited appstore funds, a gargantuan bitcoin wallet, and the number of my soulmate/forever person, if such a lady exists.

Large - Kindness, large acts of kindness are needed to change social consciousness.

Medium - Honesty, the middle path that understands the reflection in the mirror.

Small - Love, potentiality for infinite growth amongst populations of humans who are Kind and Honest.

A cat either alive or dead
An infinite amount of universes
All the evils in the world.

Name my boxes. ?

Large: The Cure for Global Warming

Medium: Tesla Model X [google.com]

Small: Electric FAT TAD [electrictrike.com]

I'd want them all empty. I need them for packing as I'm about to move.

In the large box I’d take $100 bills, the medium box I’d take a list of Falconry supply vendors and in the little box I’d take a prepaid MasterCard with no limit.

I haven't open them yet!

This will be fun!
Large box: A steel sided briefcase, locked with a combination lock.
Medium Box: A cell phone which immediately rings. The electronically altered voice on the other end tells me the combination to the briefcase which contains a folder with the details of the woman I am to seduce and bring into the fold, whatever that means. There is a passport, a few stacks of $100 bills, and an impressive dildo which would frighten a less experienced man. The voice tells me she will be in Vegas on Friday. I have two days to get there and until Sunday to seal the deal.
Small box: A key fob and the address of a parking lot in downtown Atlanta, the space indicated contains a Lamborghini, canary yellow.

Small box: Stock certificates for 1 million shares of Apple and Amazon, each.

Medium box: Gold certificates for all the $10,000 bills authorized, but never put into circulation.

Large box: $100 bills.

In the big, person size, box will be my perfect female, thin, beautiful, along the lines of Natalie Wood and Catherine Zeta-Jones, who is intelligent, playful and not religious. In the medium box will be enough money for us to live comfortably. In the small box will be a 2 to 3 Carat tension set diamond for when I convince her to marry me. Do I need to click my heels? Scary to me that up to now most people won't or can't answer your question.

Hopefully, not fresh body parts.