Nylon Paint Brushes:
Here’s a great starter kit from Hero Neo, but Windsor & Newton make my favorites.
There are many to choose from and lots of cheap ones out there, but you will want to aim for a little more when you see how fast the glue holding in the hairs fails with cheap brushes. I tend to have a fan, several flat heads, a large round head, and a fine tip for lining. Play with them and see what works best for you.
Make sure to stick with nylon to start and always be fastidious about keeping your brushes clean.
It makes the difference between having a brush for only a week and having some for close to 30 years, like mine.