Cryomancers: this adds a new faction of enemies focused on cold damage and cold-themed gear. This is the only one I paid for and I couldn't help but feel ripped off. It really just boils down to going to the Well, reading a note that points you to them, and then fighting them in a sequence of dungeons, with a note at the end of each dungeon pointing you to the next one. The suits are kind of nice, but that's about the only nice thing I can say about it. Waste of $8 USD.
Falkland Systems Ship Services: adds a new vendor in New Atlantis that sells new ship parts. The exteriors are mostly recolors of existing parts, but the internal habs have a very Millenium Falcon/Nostromo-inspired vibe to them. Nice, but I found it unnecessary since ships don't factor much in the game.
Neo-8 Airspeeder: allows you to buy a flying vehicle you can use on planetary surfaces from the Ship Services vendor. It's nice, but you may as well download the Snowspeeder from the Nexus instead, since it fulfills the exact same function.
McClarence Outfitters: this is one of the two Kinggath ones I downloaded. Adds a vendor to New Atlantis where you can take gear with special prefixes, yank them off, and put them on gear you're actually using or want to use instead. Along the way, you get a funky art-deco space suit. It's fully voice-acted, and while the suit's nice, unfortunately the Creation's main function can be performed by free mods on the Nexus or just adding special prefixes to your gear yourself with the console.
Tracker's Alliance: The Vulture: Bethesda putting this behind a paywall is scummy to the max, especially since the free one actually wasn't terrible. You're tasked with tracking down a criminal, and you take him down by ambushing him after you track him down. You are given a choice of ambush sites, and the gun is actually a pretty nice sniper, but $7 for half an hour of content and the gun didn't even fucking work on launch? No wonder nobody has faith in Bethesda anymore.
Watchtower: Orbital.Strike//Fleet.Command: Of the Creations I tried, this is the only one I actually felt guilty not spending money on. It adds a new enemy faction, the titular Watchtower, a black ops group that's dedicated to pursuing and containing Starborn because of the sheer chaos and destruction they can cause. Unfortunately, this includes you. After they ambush and capture you, you're rescued by a mysterious benefactor, who takes you to his remote station and hooks you up with what you need to build a fleet of ships that will follow and fight alongside you. You also get new parts and consumables that let you call in a variety of orbital strikes, Helldivers-style. This is also a Kinggath Creation, so everything is voice-acted and the Creation's story is well integrated into the main story, even adding more content if one Unity-jumps. While assaulting Watchtower bases is fun and the orbitals strikes kick ass, the "fleet command" aspect is underbaked. All you can do is assign crew to ships you're not flying, and set their behavior from the base's console. There's also a lot of Watchtower bases and sensor arrays to take down, to the point I wish there was less of them (I'd say Kinggath could have cut the total in half and it would still feel like Watchtower has eyes everywhere). The remaining thing I'll say is I like the Creation's custom music and it's suitably epic and heroic when you assault the final Watchtower base. I liked this one a lot, even if it is held back by Starfield's crummy on-foot and in-space combat.