I can recommend using the Set of Watercolor Brushes made by @Pesi, these are a real bummer when it comes to water-color, and you can get them for free if you enter 0 as the amount you are willing to pay.
Those you find in Krita are also not bad, they are found by typing j) into the search-box at the bottom of Krita’s Brush Presets Docker.
Michelist