The meat counter can feel intimidating because so many of the labels overlap. "Top round" and "round tip" mean different things at different stores. We are going to skip the deep anatomy and focus on the cuts you actually need for the kind of cooking you actually do.
For quick weeknight cooking you want tender, lean cuts that cook fast. In beef, that is sirloin steak, flank, skirt, and tenderloin. In pork, that is loin chops and tenderloin. In lamb, it is loin chops or leg steaks. These cook in 8 minutes or less and want only salt, pepper and high heat.
For weekend braises and roasts you want tougher, more collagen-rich cuts that reward time. In beef, that is chuck roast, brisket, short ribs, and oxtail. In pork, that is shoulder (sometimes labeled Boston butt) and ribs. In lamb, it is shoulder or shank. These cuts cost less per pound and turn into deeply flavored stews, ragus and pulled meats. Buy them with a plan to use the oven, the slow cooker or the smoker.