The easiest alternative for greasing pans is cooking oil. Olive oil is suitable for cooking meat, vegetables and pastas. A more neutral tasting vegetable oil may be better for mildly flavored baked goods. Try avocado oil or canola oil in a pinch. Pour a small amount into the pan and coat the entire surface; use your fingers to spread it out on a cool baking pan, if needed.
Bacon grease works well when cooking pancakes and meats on the stove. It's not so great for baked goods because it can add a slight bacon flavor to the food (unless that's what you're going for!). Save bacon grease in a jar and store it in the refrigerator. When it's time to grease a pan, scoop some out and spread it onto the pan as needed.
Shortening works well for baked goods and for cooking on the stove, too. Scoop some out and spread it onto the pan as needed.
Lard is virtually tasteless, so it's good for both baked goods and pan-fried foods. Use it just as you would bacon or shortening.