Amazon.com: Redragon M908 Impact RGB LED MMO Gaming Mouse with 12 Side Buttons, Optical Wired Ergonomic Gamer Mouse with Max 12,400DPI, High Precision, 20 Programmable Macro Shortcuts, Comfort Grip, White : Redragon:
Amazon.com: Logitech G600 MMO Gaming Mouse, RGB Backlit, 20 Programmable Buttons, Black : Video Games
Honestly I don't see how people can use 20 side buttons : r/pcmasterrace
Razer Naga Pro Wireless Gaming Mouse Up to 20 Buttons Side Buttons Can B [New!!] | eBay