Poster pen sets and poster art became popular during the latter half of the 1970s, part of a general arts and crafts surge that included everything from latch hook rugs to paintable figurines. (The oversized, “fine art” coloring books innovated by Troubador Press were an obvious inspiration.) There were poster sets before Star Wars, but Star Wars kicked the format into overdrive, making it relevant and exciting to the emerging geek generation.
(Images via eBay)
2 Warps to Neptune 
I remember seeing this at Kmart. The art for these was usually pretty good. The Close Encounters one was unique because it came with a free photographic poster (as pictured in the second photo).