Bob Powell primarily worked for Marvel, Harvey & Red Circle Comics in the Silver Age. He drew a lot of war, horror & super-hero comic books along with penciling (over the rough pencils of Wally Wood) the original Mars Attacks trading cards.
A favorite of mine was Bob's work in Shocking Tales Digest #1 featuring some Man in Black tales. A gem of a digest also featuring Jack Kirby & Joe Simon as well. Love it! A prize in my personal collection.
With Marvel, Powell worked on a certain blind super-hero named - Daredevil, Man with No Fear #9-#11, #81 (Torch & Thing back-up story) & Annual #2. Additionally, he drew a quirky Human Torch & Thing story in Strange Tales #130.
At Harvey, Bob drew Man in Black featured in Thrill-O-Rama #1 & Glowing Gladiator (designed by Jim Steranko!) in Double-Dare #1.
For Red Circle, Powell illustrated the Fly in Adventures of the The Fly #24 & Blue Ribbon #10.
Eclipse presented Bob Powell's Timeless Tales #1 reprinting three Golden Age stories from Black Cat. AC Comics has also reprinted a lot of his Cave Girl stories.
Although the largest body of Bob Powell's work was in the Golden Age, I believe he made a big mark in the Silver Age as well.
Live Large my Friends!