Something like these
Tamiya Modeling Brush HF Standard Set https://www.amazon.com/dp/B000J49XD2/ref=cm_sw_r_other_apa_hBcaybA340TSB
You can find packs of similar brushes at hobby stores and even craft sections at walmart.
Also I recommend toothbrushes (cheap ones) to wash your sprus, and toothpicks to mix your paint, and finally some tight knit q tips to remove loose paint.
Oh! Also use droppers to get paint in small doses.