Unlicensed Mega Drive clones (Famiclone models)
From Sega Retro
In the 1990s, there was a huge increase in the production of Nintendo Famicom console clones. At some point, production of clones resembling the Mega Drive began and the main goal was to convince the customer that he could buy Sega consoles for a lower price, but in fact he was getting an ordinary Famicom. Later, such a grip was used with the Super Nintendo console to create famiclones series like SP-60, and most famous one with PlayStation called PolyStation. Most of the consoles came with 2 pads, a black gun, and one multi-game cartridge.
Mega Drive shell
Looks like a regular Mega Drive or with minor changes. Usually under a changed name, e.g. Tarzan, Zhiliton.
Mega Drive 2 shell
The first and most popular models were sold in the same box as the Asian Mega Drive 2 without a changed name. Usually the box could be distinguished by a pistol that looked like Light Phaser, which was added to front cover of the box. Later models were sold under different names and in different boxes, but the design of console remained the same. Interestingly, some vendors that sold Mega Drive and Famicom clones, had this fusion clone on sale, causing additional customer confusion, for example Fei Hao FH-2012 or Simba's Mega Power II.
Famiclones from early 2000s that tried to cash on Dreamcast. They resemble Dreamcast console (like for example Game Corner) or Dreamcast controller (like for example Power Player Super Entertainment System).
Own shell plus Sega accessories
Design of these consoles doesn't resemble any of above but system has accessories similar to those by Sega, usually controllers.