Ollie Osnick (who had a single-issue run of being the Spectacular Spider-Kid) had no powers. He just dressed up in a Spider-Man costume and had a set of jury-rigged Doctor Octopus-like metal limbs.
Richard Dragon, who had at least some role in teaching Bruce Wayne martial arts (and now, IIRC, has his own title) didn't have any powers that I know of.
Steel (DC Comics) is yet anothr guy in powered armor with a weapon.
The Prowler (Marvel Comics) is just a guy in a suit.
IIRC, the Spider-Man villain called the Tarantula had no super powers. He used some weird drug to give himself greater stamina and strength (IIRC), and used sharp-tipped shoes coated in poison.
All the members of the group known as the Jury (Marvel Comics) are just people with special costumes, that I know of at least.
Both Mace and Xandu (Marvel Comics) are just people that can use a special weapon - they have no innate powers.
Moving to more esoteric comics, many of the heroes and villains in Antarctic Press's "flagship" comics, Ninja High School and Gold Digger, don't have super powers.
The following NHS characters are normal people with just some ninja training: Jeremy, Ricky, and Anna Feeple. Ichi and Hitomi Ichinohei. Yumei and Bento Katana. Yoji. Asagi. Likewise, Prof. Steamhead is extremely brilliant, but that's all. The Zetramen were just a power ranger-like superhero team, with no inherent powers.
Gold Digger is a bit harder, since many of the characters are of other races that grant them special abilities, or have magic or something. Gina Diggers is a normal person, but she also has ungodly intelligence, giving her scientific genius and equipment that are almost unmatched. Erwin Talon has the same, though he uses it for evil.