Here is a quick shot of pure JPL-quality fuel for the imagination. "Aliens in Space" clocks in at less than seventy pages, and at least half of that space is taken up with illustrations, but I'm not complaining. Species range from the benign to the vicious to completely incomprehensible to the human observer. Each batch of fauna is introduced by a description of the hosting homeworld: its mass, temperature, and diplomatic status in a massive fictional intergalactic Federation.
The most unsettling and hostile world has to be Hades (surprise, surprise). Its native "Fangstones," vampires that conceal themselves as greisen-colored boulders, are responsible for killing most of the humans who've been foolish enough to touch down there.
The most enchanting homeworld is Aquatica, a kind of Vernian underwater planet whose most highly developed creature is a gill-throated, web-footed biped that looks a bit like the Creature from the Black Lagoon (although it's more quixotic than menacing). The hadal depths of the planet's massive ocean play host to relicts left by a long-forgotten highly-advanced civilization. The piece-de-resistance is a pyramidal structure whose "origin and purpose" (h/t "2001") remains a total mystery. All that's known about it is that, when someone or something gets close enough, a beam of light appears from an oculus-shaped aperture to follow the motion. The pyramid is rendered in lush blue-greens, a dark kind of Daniken-esque artifact that could serve as the basis for a film or novel.
Indeed, the book is brimming with artwork and loving descriptions that are sure to inspire as much as entertain. That's assuming you can find a copy. Highest recommendation.