Soft Science Fiction

No such thing! Soft sci-fi is an undefined term that does not fit into the lattice of genre assessment.

But since some people are painfully slow in realizing that science fiction is more related to the fantasy genre than any scientific publication, the term might be thrown around to describe the opposite of Hard science fiction when what is really meant is any science fiction without the restrictions of "hard" science.

If one were to brave the impossible challenge to devise a comprehensive overview of genres in fiction, hard sci-fi would be a subcategory of science fiction, not its opposite.

A possible way to describe it is "a story where the science is informed by the fiction." Or in simpler terms, it is Sci-Fi with Space Magic, Mumbo Jumbo and things that will rape physics from back and forth.

Settings with SSF elements

• Warhammer 40,000 is of course one of the quintessential Soft Sci-Fi, with the blatant 'Space Fantasy' genre being pasted everywhere, the very nature of the Warp, medieval style buildings, flying cathedrals and tanks that came out of World War 2. That's of course not counting the constant rape of physics and the square cube law with the very idea of Titans walking the battlefield without tripping over from their own weight.
• Star Wars is Warhammer 40k's more fantasy cousin (I know, an impressive feat on its own), filled with the Force (not counting the midichlorian bullshit from the Prequels), super death lasers that can blow up planets and its 'Once upon a time' setup for the movies which makes it like an adult fairy tail more than Sci-Fi. Also known for its legendary fandom rivalry with Star Trek due to the above reasoning on Soft Sci-Fi vs Hard Sci-Fi.
• Doctor Who has the ridiculously powerful Time Lords, the constant rape of physics, its blatant ignorance of the space-time concept where space and time are one and the same and ignoring common sense logic like how an egg should NOT gain more mass when it develops. Heck the fluff even states that the Timelords erased the concept of magic from the universe itself!
• StarCraft being a WH40k look-a-like has plenty of physics raping space magic bullshit, what with the whole concept of psionics and the Zerg's improbable biological adaptations that even the Tyranids may find blazingly fast.
• Halo at first may seem like Hard Sci-Fi, what with the modern firearms and vehicles still being used in the 26th century, but that is just a facade since Halo is one of the most blatant franchises that has no concept of physics and juvenile science. The list includes 400 meter long ships weighing as much as air, Covenant 'plasma' not being actual plasma at all, anything from the Forerunners and the very presence of the Flood essentially raping physics and biology in the ass at full force.