The ace-80 from 1985 or so for the Atari 800.  

http://www.atarimania.com/mags/pdf/analog_no_42.pdf

Reviewed in here. 

On Jun 25, 2022 09:31, John Heritage via vcf-midatlantic <vcf-midatlantic@lists.vcfed.org> wrote:

Hey all --

Which (popular) 8-bit computers gained "easy" or even "standard" 80 column
support?

I know there are a ton more 8bits than I'll list below, but my
understanding is:

Atari 8bit -- XEP80 official accessory but almost no one bought it;  used
joystick ports.. slow and limited 80 column (black and white?).  Atari did
have a 60 column graphics/text mode IIRC.   there is a software hack that
uses narrow characters for '80 columns' but hard to read, and came out
after the machine was no longer commerically sold.

Apple II - supported via cards.  If 80 column support became common, when
did it become common?  what was normal for color count, etc?

C64 - C128 mode natively offered 80 column support;  millions of these
sold.  So maybe common later on?   16 colors.

PET - no 80 column?

C Plus/4 - software hack?

ZX Spectrum --  available via some clones only, not common?

BBC Micro -  Looks like a native mode for 80 column support?

TRS-80 - no native 80 column support?

Thanks!
John