Here is a large collection of black & white scanned clip art. I originally gathered it in the early 1990’s, while using Atari MegaSTe and TT computers. I scanned quite a few of the images myself, but others were gathered from collections posted on bulletin boards. Most of them are 300dpi resolution.
To download a full-size image, keep clicking on the one you want until it is showing in a blank page in the browser (if your mouse turns into a magnifying glass cursor with a plus-sign in it, click again until you see a minus-sign). Right-click on the image and choose “Save As…”
You can also download the whole collection here in one zip file (~90MB): BW Scan Collection.
I get a few questions about this regularly. Here is what I know. Some of these scans I made myself. Others were taken from bulletin boards, CD collections, etc. This was from the early 1990’s, on an Atari computer. In those days, copyright was not such a hot issue as now. I expect most of the sources these came from do not exist today, or are not commercially active.
Some of the Bible pictures, I later found, came from Horace Knowles, who was commissioned by the British Bible Society to illustrate the New English Bible in the 1950’s. These illustrations were used in a few other versions as well, even up until 1995. Their copyright statement is here. You can use these images for commercial work, but read their statement carefully.
I don’t think you would have a problem using the others commercially, but cannot guarantee it. “Let the Buyer Beware!” To this day, NOBODY has ever written to me claiming that such and such an image was theirs, and “could you please take it down.” Still…it could happen. So use them at your own risk.
I believe you are always safe if you use them “for educational use”, at least in the USA, under the “fair use” clause of the copyright laws. But I’m not a lawyer.