Depends, I have a Game & Watch, the donkey kong one, but also a NES in storage. I guess both of them are from the 80's :)

Atari 2600

We'll go with Super Nintendo, although I'm almost positive the Atari is still at my parents house.

A Coleco Telstar?

Wii, because i dislike clutter.Got rid of my old consoles years ago.

Sega Master System. I want extra points because:
a) it still works
b) it's the Brazilian edition filled with rare cartridges like Street Fighter 2

NES I guess. I own a couple of old Game and Watches as well though which are about as old (if not slightly older).

One of them is the Game and Watch Ball (the first, from 1980) but it's the club Nintendo re-release so it doesn't count.

This is tricky. I have a AV Famicom. Which is from 1993. But the Famicom Disk System is from 1986. What counts lol.

Oldest I have is the NES.

For what I have total: NES, SNES, N64, Playstation 1, Playstation 2 (3 of em), Playstation 3, Playstation 4, Wii U, Vita, 3DS.

I will soon also be adding the Genesis, Sega CD, Saturn, and Dreamcast to the collection.

I have three separate sega genesis consoles, that are all functional. Don't know how many carts I have for it, but, it's around 90, but I know for sure it's more than 85, but less than 95.