Oleogel, Venetian Medium and Conservar Laropal Varnish
Oleogel is my all around, go to medium. It is the best, especially if you are taking a class or workshop. The tube makes it easy to transport. My students love it as well.
Venetian Medium when added to your oil paint leaves a beautiful sheen when it dries and definitely speeds drying, making it great for glazing. I would not use any other varnish other than Natural Pigments' varnishes. I particularly like the sheen, not highly glossy finish, when one coat is used. If you want it shinny, you can use more than one coat, Great varnish! Thank you Natural Pigments for making the best products on the market for painting for longevity.