Well, every gamer has his own preferences as far as the best mouse is concern. So, my point is that it is useless to give some recommendations here. I can only share some trusted recourse with you, that can help to make a choice. Check out this list csgopedia.com/best-mouse-models-for-playing-the-cs-go/ which based on parameters and the preferences of pro players which were analyzed from the base of CS:GO pro players' setups. Still please mind that you need to remember that first thing you need to choose is a comfort for your hand form. Personally I am crazy about SteelSeries Rival 3 Optical because it offers many settings and its highly functional included software enables you to even load your custom settings table with your nickname. But it is only my choice
Depends on what grip you are. If you are a claw gripper, I would suggest the Zowie EC2-A, Deathadder Chroma, or the G403. If you are a palm gripper, I would suggest the G402 or G502. If you are a palm gripper, I would suggest the Abyssus or the G303. It all comes down to preference because no one is perfect about the “best” mouse.