Sega just revealed its next miniaturized console to be the Mega Drive 2 (or the Genesis Model 2). The latest mini model is announced only for Japan currently, and ships later this year.
NEW SEGA Mini Classic Console Announced! SEGA CD & MORE! Mega Drive Mini 2 With 50+ GAMES!
Sega announces Game Gear Micro handheld retro consoles - Neowin
SNES News Nintendo Life
Sega Mega Drive Mini announced at FES 2018 - Neowin
Sega's miniaturizing its Mega Drive 2 next - Polygon
Sega - Mega Drive Tower Mini 2
SEGA has announced the Mega Drive Mini 2, comes with 50 pre-installed SEGA CD and SEGA Genesis games
Sega Genesis Mini 2 Lineup Includes Sega's Most Controversial Game
Sega, still doing what Nintendon't, announces a tiny Sega CD retro console
Sega reveals Mega Drive Mini 2, and it will include 50 Mega Drive and Mega CD games