Gentle makeup for rosacea can be really hard to find. In general, the fewer ingredients, the better.
Liquid makeups can be challenging because, if your skin is bumpy at all, it can be hard to get a smooth application. Some of the ingredients can also cause problems. Makeup marketed as "anti-acne" usually contains salicylic acid, which may be too harsh and drying for rosacea.
To get a smooth feeling (or slip) to liquid makeup and to make it easier to apply, dimethicone or other silicones are often added, but these can aggravate rosacea. I think it's simply because, like many hydrocarbon ingredients, they irritate skin in general. By nature, they coat the skin, decreasing the breathability of your skin, and I think that's a problem for many skin conditions, including acne, rosacea and eczema.
Powder makeups can be a solution, but you have to watch their ingredients, too. Now that powder makeup is popular, every brand makes one, but some still contain a lot of preservatives or unnecessary ingredients. Look for methylparaben or propylparaben, for example, and avoid products with them. Many, many mineral makeup companies advertise as being good makeup for rosacea, but I have tried quite a few without much success.
I avoid cornstarch because it's food for bacteria. You might see it listed as "zea mays," which sounds botanical. I prefer makeup that is pretty simple--zinc oxide, mica, iron oxides and silk powder constitute a basic list of ingredients. Zinc oxide is very soothing for rosacea (as well as being sunblock), mica gives some color and coverage, and silk powder has proteins in it that soothe the skin, too.
Some people, including me, can't use titanium dioxide. It gives me bumps under my skin and makes my forehead, where I have rosacea, more red. I think that's because titanium dioxide is very unstable and has to be coated with something, but you almost never know what was used to coat it. I suspect it's often dimethicone.
While more of the conventional beauty brands are starting to come out with some decent options, there are other niche mineral makeup brands that I've come across. I have tried some of these, and others I have not, but they seem to offer options that are not irritating:
It also matters how you apply makeup. You have to be gentle with your fingers and brushes so that you don't traumatize your skin unnecessarily. I also wash my brushes more frequently. I do not do the "buff and swirl" technique when I put on makeup--that roughs up my poor skin. I just lightly brush it on.
If you have red patches, some powder zinc oxide can really help to cover it. You can also try some green-tinted powder, but I personally have found that hard to blend so that I don't look, well, green like an alien. Weirdly enough, I tried a lavender powder, and it actually looked good. I find it hard to believe that lavender would cover redness, but it does. A third option is a yellow concealer, which works for some people.
To help you search for makeup for rosacea before you try anything, you can search for makeup on Makeup Alley. Thousands of products have been reviewed by real users like me, and there are a lot of reviews by others with rosacea. Reading through the reviews is actually fun and a bit addicting!