Note this article is specifically for illegal multicarts, legitimate ones licensed and approved by Nintendo/SEGA do not count.
Unlicensed Multicarts stands for Unlicensed Multi-cartridges. These are cartridges that contain multiple games, but are not licensed by the company that created the console that it was released for. These were prevailant in countries such as China, Hong Kong and Japan where piracy was extremely common. The Famicom was not discontinued until 2001, so they continued to sell through the 80s and 90s all the way up to discontinuation.
Fake xxx in 1 cartsEdit
These pirated cartridges are the most common Multicarts. They often claim numbers from 100 to 9,999,999 which is virtually impossible considering the capacity of a Famicom cart. Lets start with the appearance of the cartridges.
These cartridges vary from regular [legit] Famicom carts. For starters, they don't have the Nintendo label, and instead have a gridline pattern on the top, lacking any Nintendo logo hence the name "Unlicensed Multicart". These carts generally feel lighter than legit carts and also have impressive art work on the front.
Let's take the 9,999,999 in 1 cartridge for example. When you start the cart up, it looks promising with the first 10 games all being unique and [assumably] good quality. However, once you scroll down past 10 you'll see the same games repeated. That's it. Most of these carts only have 5-10 games but repeat the games to make up the numbers. You'll see slight variations in the title such as "Moon Mario AG", but [most of the time] you will generally see no difference in gameplay.
I recommend you buy official multicarts. They may have less games on it, but you won't get scammed.
Other Unlicensed MulticartsEdit
Believe it or not, some multicarts actually have the number of games they claim. However, these are usually extremely low quality and buggy games. Some include the 31 in 1 cart that has a list of the games on the back. I have actually wrote an article on an unofficial multicart, one of the most famous, Action 52.