If you have oily skin, using a primer can help control excess sebum and create a smooth base for your makeup or foundation. Here are some of the best primers for oily skin, along with their positive and negative aspects, and ingredients or materials:

1. Benefit Cosmetics POREfessional Pro Balm Face Primer Pore Minimizer: This primer is suitable for acne-prone skin and contains Camellia oil and vitamin A essence of the white tea plant, which help fight against free radicals and make the skin look firmer, brighter, and more resilient. It is the most hydrating primer for oily skin, but it might be a bit sticky.

2. Maybelline Baby Skin Instant Pore Eraser Primer: This non-comedogenic primer is infused with micronized bamboo powder and blurs imperfections. It is safe to use as there are no harmful ingredients added to the product. However, it might not be lightweight.

3. Smashbox Photo Finish Oil & Shine Control Matte Primer: This natural primer for oily skin has no artificial colors, fragrance, alcohol, or any other harmful chemicals added to it. The product is gluten, oil, nut, and nano-free. It is lightweight and suitable for oily skin.

4. Hourglass Veil Mineral Primer: This primer is long-lasting and provides SPF15 protection. It contains African whitewood, oleanolic acid, and peptides, which are suitable for oily skin. However, it is pricey.

5. Estée Lauder The Mattifier Primer + Finisher: This primer can also be used to set makeup and is oil-free and long-lasting. It is pricey, but it is suitable for oily skin.

6. OFRA Absolute Cover Face Primer: This primer contains Dimethicone & Dimethicone / Vinyl Crosspolymer, Titanium Dioxide, Dimethicone, Hexyl Laurate, Polyglyceryl-4-Isostearate, HDI/Trimethylol, which are safe to use. It is lightweight and suitable for oily skin.

When choosing a primer for oily skin, look for key words like "blurring", "mattifying", and "pore minimizing" on the label. All of these are indicators that the formula has either oil-absorbing benefits or is designed to help makeup products grip onto oily skin. Phrases like "oil-free" and "non-comedogenic" (tested to not clog pores) are good to keep an eye out for as well. Consider a formula that contains SPF to protect your skin from the sun.