by far my favourite old console is the coleco telstar arcade.
By Evan-Amos - Own work, Public Domain, Link
a first-generation console by coleco, a toy company branching out into the video game industry as many did circa the mid 70s, this frankenstein of a console was released in 1977. it retailed for around $50, much cheaper than most other consoles on the market. many of its peers at the time featured lightguns, certainly, and even more had the capability to play PONG-type games - but not many had full steering wheels implemented for racing games, nor did they have all three of these features simultaneously! but the telstar arcade does, and that's what makes it such a unique entry into the rich history of consoles.
By Doug Kline, user popculturegeek.com of flickr - CC BY 2.0, Link
the telstar arcade is made in a strange triangular case, with each face containing each of the interfaces for different types of games. while most console cartridges of the time were sort of black square cartridges that were inserted into a vertical slot, the telstar arcade instead made use of silver triangular cartridges which slotted horizontally into the top of the console, like a flat-topped pyramid. a very triangular console, all in all.
From pong-story.com
speaking of cartridges, only four of them were released for this console; the first sold with the system, and the remaining three available separately at $25 a pop. cartridge one contained road race, tennis, and quickdraw. cartridge two contained hockey, tennis, handball and target. cartridge three contained bonus pinball, shooting gallery, shoot the bear and deluxe pinball, and finally, cartridge four contained naval battle, blast away, and speedball. few, if any, records likely remain today of the contents of these games.