These are colloquial, side-edited, and rather exotic ways of measuring cutting-edge items in current technology.
Alternatively, I would name them AAGM units. Or use V3.0 to add fake specificity if you like… The AAGM units are:
1. A transducer about the size of a matchstick. However, this was published 62 years ago in his April 5, 1961 issue of Electronics Weekly. The title of the article was “Matchstick-sized blood pressure transducer.” It started. “A matchstick-sized blood pressure transducer and ultrasound blood flow measuring device were among the topics discussed at a meeting of the UK’s leading cardiac surgeons and engineers in London last week…
2. 
What about something the size of a tic-tac-toe box, smaller than a pack of cards and bigger than a 50p piece? We’re not talking about mints here, we’re talking about digital guitar amplifiers. “The Fender Mustang Micro is a small amplifier with an articulating guitar plug on one end and a headphone port on the other.”
3. credit card. As in “a credit card-sized micro:bit educational computer.” I think the obvious things are hidden in plain sight.
Four. 
Talk about packs. A pack of cards like playing cards. Another obvious one, but so far only referenced in this Raspberry Pi VNC contest winner.
Five. There’s also a shirt pocket-sized optical storage device, courtesy of NASA.
6. wallet size. Similar to the STMicroelectronics 316Mpixel 18K image sensor that is at the heart of Sphere Entertainment’s Big Sky camera system. “Die dimensions are 9.92cm x 8.31cm (82.4cm2), twice the size of the wallet-sized photo, and there are only four complete dies that will fit on a 300mm wafer.”
7. And why didn’t I think of this before? Technology is used to measure technology. It’s self-referential, so to speak. We are talking about mobile phone measurements. It’s like a quantum magnetometer the size of a cell phone.
8. 
The size of a washing machine – ClearSpace’s CLEAR mission is funded as part of the UK Space Agency’s National Debris Removal Programme. ClearSpace’s robotic capture system will be used to safely remove two British satellites, each about the size of a broken washing machine, from orbit.
9. Tennis court size! In 2013, Northrop’s Grumman mock-up of NASA’s James Webb Space Telescope adorns the Austin, Texas skyline. The model is about the length of a tennis court and about three stories high.
Ten. Finally, I traditionally think of countries, regions, and continents, but what about the planet? The not-so-big old blues that are sadly overlooked and often taken for granted in the world of computing…
Also, as before, please provide further alternative GM scale units in the comment box below. There must be some Gadget Master scale measurements that I’m still missing.