The first edition of Aftermath (1980) was produced by Phoenix Games. Most of these sets that I’ve seen have Fantasy Games Unlimited stickers over the PG logo.

The lid art is different from the FGU sets that would follow (1981): The man is drawn slightly differently, and the woman is missing. The contents are identical to the later edition.

Aftermath Phoenix restickered box prof
Here’s a set that came through the shop in March 2016

Aftermath RPG accessories in the shop

The Aftermath RPG product line cataloged at my reference site

EDIT May 24, 2020

Aftermath lot
A later FGU Aftermath set with accompanying module adventures
Aftermath d20 w TSR d20
Some Aftermath sets sold with tiny d20 (numbered 0-9 twice) – from Gamescience I think. This one is white and the numbers are not crayoned. Here it is shown with a TSR d20 of the time (ca. 1981) for scale – the TSR d20’s were kinda small themselves.

Aftermath RPG accessories in the shop

See also: CITY STATE: A drop-in Chicago Sourcebook for your T2000 campaign

Early print of Aftermath! Magic!

Gamma World colored map

Omega War: Science Fantasy Adventure Game (1983)