Regional and Police sets are actually oddball sets. These sets are special because they were only available in certain cities or regions, rather than nationwide. In theory, these sets tend to be scarcer and harder to find because they were not printed in quantities similar to the nationally-distributed sets. As a result of this scarcity several regional sets are quite valuable, while others are worth only a few dollars due to a lack of collector interest.

Locally-issued team sets are not high on most collectors' priority lists, meaning the values of these sets usually remain modest. On the other hand, locally-issued sets that contain league all-stars or successful rookies may become quite valuable because of greater collector demand, in addition to scarcity. The "Standard Catalog of Baseball Cards" (editions exist for the other major sports, too) is a must-have reference if you would like to learn about the thousands of locally-issued sets and their values.

It is all but impossible to keep track of the many oddball sets that are being released every week somewhere in North America! You will probably want to specialize in the kinds of oddball sets you collect. Personally, I enjoy collecting oddball sets that were released in the 1980s, regardless of the sport. I've noticed many truly scarce card sets from this era for sale on the internet at prices much less than book value.

Whenever possible, consider collecting these sets in the original form in which they were released. If the cards came in groups of three on the back of a cupcake box, consider cutting the whole panel off the box without seperating the cards (or neatly fold and keep the entire empty box!) Regional cards have also been released on cardboard "hangers" that hung on pop bottles, in clear cello packs, on table placemats, on kid's meal boxes, as uncut sheets tucked inside local newspapers, and handed out one at a time by public safety officers. Unless storage space is a problem, keep in mind these cards are usually more valuable when kept in their original issue form. If the cards have "scratch-off" games or perforated coupons attached, you should leave these little temptations untouched to maintain the value and integrity of the cards.