I'm glad you asked!
By "retro range" I mean the age/generation range that you are interested in when it comes to retro gaming. In other words, what are the oldest games you like to play? What are the newest, short of the current console generation?
The retro games that interest me, that I like looking at, and that I like to play start from the Atari 2600 era through the end of the Genesis/SNES era for the most part.
I still like some of the classic games from the classic "Atari era" - but unfortunately, LOTS of them haven't aged well at all in my eyes. But classics like Asteroids, Yars Revenge, and Defender will never get old for me.
Meanwhile, I love the 8-bit and 16-bit generations too. The problem for me comes after that. IMHO, most of the PS/N64/Saturn early 3D games have aged really badly and I don't enjoy playing them like I did when they were current.
So, my retro range is Atari - SNES/Genesis or, games and systems current in NTSC-land from 1980(ish) - 1995/96 or so.
What's yours?