i love doodling with ball point pens :), i used to have a series of 4 drawings called red doodles, they're lost to time now though unfortunately :(
but i still loved doodling with the red pen the most, its lines where the cleanest, black then blue were a close second but they felt too watery i think, and i didnt like green because it always felt thick and hard to write with and not as flowy, so yeah try others for sure!