Silver Age Flash: Non-Rogues' Gallery Foes

In the early days of the Silver Age, The Flash, the reimagined hero whose adventures brought in the Silver Age, was as likely to fight aliens or gimmicky one-shot crooks as he was to fight the super-scientific crooks who came to make up his famous Rogues' Gallery. Since I like making micros no one else has yet done, here are some of those lesser Flash foes.
The Turtle Man: "The slowest man alive" was a natural foil for the new version of The Fastest Man Alive. The Golden Age Flash had fought a crook with a similar gimmick. In fact, some of these early Silver Age Flash adventures read as if Robert Kanigher had dusted off an unused script from the 1940s. This crook, from the Flash origin story, had some of that quality.
Mazdan: Then there were foes who seemed like dry runs for the Rogues' Gallery. Like Abra Kadabra, Mazdan came from the future. Like Heat Wave, he controlled heat.
The Time-Giants: And then there were the aliens, from other worlds, other dimensions, even other parts of our world. The other-dimensional Time-Giants started out small like a second, grew larger like a minute, then closed the hour big like the hour itself -- before shrinking and starting the whole cycle over again the next hour.
The "Brain Brothers": From another story which read like a '40s leftover. These unnamed triplets distracted the police with a giant puzzle box, while they used their gimmicks (a breakaway high-wire escape route, spring-heeled shoes, and an electric suit) to rob elsewhere in the city, but the Flash was able to track and trap them.
Le Chat Noir: The Black Cat who threatened Paris with a stolen atomic bomb.
Katmos: A metallic life-form, surviving from a super-scientific civilization of 8 million B.C.
The Bird-People: From a hidden underground civilization, they were enslaved by the Super-Gorilla Grodd.
The Saremites: From an underground undersea civilization, they were menaced by the Maugites and captured a space capsule after its splashdown (Are you old enough to remember those?) to use the astronaut as a messenger to get help.
The Cloud Creatures: living clouds escaped from a volcanic vent, their lightning and super-powerful thunderclaps menaced Earth until Flash destroyed them by hitting their nuclei (that nose-like black dot in the center) -- but he had to run on clouds to do it.
Kyri the Humanoid: Sent by the Rulers of the Galaxy (a pre-GL Guardians of the Universe -- '50s hero Captain Comet had a similar group) to seal a breach in the fabric of space-time with his super-speed, but an accident caused him to lose his memory and then, once he regained that, his speed.
Kee Feleg: a crook from the dimension of Mohru who came to Earth to steal lightning-struck objects whose energy could give his gang super-speed.
Kunar: Part of an alien invasion force which shrunk The Flash and The Elongated Man but still wer defeated by them.
Elider and Modrie: Teacher Elider came to Earth to make a "photo-synth" copy of Central City for study by his advanced research class, but lab assistant Modrie used the unique time-bending quality of the copy to learn future events on Earth and make himself rich as Mr. M. Odriex.
Po-Siden: Came from the advanced world of Olimpus because he'd learned humans were descendants of a lost colony ship, and he needed to make them submit to the rule of Olimpus with his water-control wand.
The Bredans: Members of an undersea civilization which captured and enslaved humans -- until they captured The Elongated Man, whose disappearance brought the Flash investigating.
The Grodans: "golden giants" of Pangaea encountered by the Flash when a freak accident threw him and his companions back in time.
The Leader: of an unnamed race of extra-dimensional aliens who thought Captain Boomerang's dimension-skipping boomerangs were a threat, so they traced them back to our dimension and made a pre-emptive invasion.
James Lawton: his helmet sent mind-control commands through television broadcasts, but in reverse: from his TV set back to the studio.
Mynher: leader of the Dokri who, in Earth's future, sent a nuclear-power-suppressing "hive" into the past, so that his invasion force would face no opposition. When the effects caused havoc in his time, The Flash sent Kid Flash into the past to destroy the hive, while he aided the future humans against the Dokri.
The Ornitho-Men: a lost evolutionary offshoot from the period where the Dokri had sent their "hive". Kid Flash enlisted their help. A much later Flash story told how the Ornitho-Men developed a civilization but sadly destroyed themselves in nuclear conflict.
The Orinocas: all-female inhabitants of a mirror-world in which the Mirror Master once took refuge. When they were fascinated by his mirrors and wouldn't let him leave, he found a way to bring the Flash to the mirror-world to "arrest" him and take him home.
Daphne Dean: childhood sweetheart of Barry Allen who became an actress, she charmed her way back into his life, intending to fake a love affair with him as a publicity stunt, then found herself genuinely caring for him again.
The Myrmitons: alien warriors who lured The Flash and Green Lantern off Earth so they could conquer in their absence, then held Earth hostage with their mastery of cosmic ray energies.
Dro Dorno: "tele-vid" producer of Gobdor who, when his "Thrills of Earth" program failed to find any natural disasters to record for his viewers, decided to manufacture a few.
Captain Creampuff: Abra Kadabra, villainous stage-magician from the future, turned The Flash into a puppet. The Flash's opponent in Abra's puppet show was "Captain Creampuff", a puppet which threw creampuffs at him to humiliate him.
Prof. Ira West: Father of Iris West, an absent-minded professor who occasionally threatened The Flash accidentally through either his inventions or his poor memory.
The Makryds: warrior-race from the 16th Dimension. When they attacked the world of Korydon, the Korydonians sent three super-weapons to Earth to hide them, which led to The Flash's involvement in defeating the Makryds.
Metal-Eater: gaseous alien which fed on metals
Paul Gambi: Tailor who made the Rogues Gallery's costumes.
Missile Man: costumed identity Gambi created when Barry Allen, posing as a criminal, came to him for a costume. The costume was designed by The Top as a trap for The Flash.
Dexter Myles: former stage star whose bombastic personality made him a dupe of several crooks.
Ak-Zaka: criminal from another dimension who was able to become intangible
Luke Elrod: escaped convict who, through exposure to radiation, gained share-shifting powers
The K-10 Gang: other-dimensional criminals who employed an explosive which had cross-dimensional effects on Earth.
Klkan of Gyr: alien tyrant who threatened the UN to surrender The Flash or he'd destroy Earth. His people wanted The Flash to power a time machine so that they could go back and win a battle which had previously deposed them.
The Breakaway Bandit: Zedubon Zarr, alien gun-runner whose body parts could detach and move independently of each other.
Frand Mattar: criminal of the 38th Century who blackmailed his time with a bomb he'd sent into the past -- 20th Century Central City, to be -- precise.
Vardar Varr: flame-like being who befriended the prehistoric Ornitho-Men then chose to take revenge on their behalf on the humans who supplanted them.
Mopee: would-be angel who claimed to have been responsible for the accident which created The Flash.
The Golden Man: alien mutant who captured the three Flashes (Barry Allen, Wally West/Kid Flash, and Jay Garrick from Earth-2) to harness their speed-energy to evolve others of his race to his own evolutionary status.
Dream-Death: personification of death in a dream of Iris West Allen's. The Flash had to enter the dream and beat Death in order to save Iris's life.
The Nok: alien creature which escaped to Earth and fed on The Flash's protective aura.
Baron Katana and the Samuroids: Japanese war-criminal who sought to restore Japan to feudal days via robotic Samurai.
The Frog: gang boss who learned The Flash's identity, leading to a complex ruse wherein The Flash pretended to be an actor impersonating Barry Allen. The Frog did demonstrate leaping agility, but that's not of much use against super-speed.
That's it for now.