Not gonna lie, I think Traveller has the best cover art for a game, period. TTRPGs, video games, board games, card games, I legit think Traveller is at least top 10, if not number 1. I have never seen cover art that has made me feel so compelled to try out the game and make me wish I had people to play it with. It tells you about the game's theme, setting, gameplay and I imagine, conveys the way the game actually feels to play without any actual artwork.
Are there any other games that can claim the same? That's a serious question, I'm legit scratching my brain trying to think of other games with cover art that hits as hard as Traveller's, actual "artwork" or not.
Traveller's cover art is just on another level.