
Logitech G
G600 MMO Gaming Mouse
Customizable MMO workhorse, durable, but discontinued and pricey.

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I'm probably a minority opinion, but I could never really get used to MMO mice. I had a Razer Naga back when I played WoW super seriously, and have more recently (past three years) used a RedDragon el cheapo 10key mouse, and I think I've used the side buttons intentionally a \*total\* of 20 times in all these years. I find them somewhat cumbersome. You MIGHT find using a controller might be the spice you need to get back into the game.
Something like this: https://redragonshop.com/products/m811-mmo-gaming-mouse I can't seem to find the exact one on their site right now, but it's that company and that number of buttons. It works pretty nicely for me. 1-5 are abilities and transference like you'd think. I don't really use 6-8. Then the normal side buttons are melee and interact.
Check out the Redragon M811. I considered it but Redragon is a cheap brand. It has what you might be looking for tho. I didn't go for it because some skills and actives need to be used in very quick succession (Looking at you cold front), faster than I think I could comfortably move my thumb back and forth that far. I also learned from all the mice I tried, your thumb as not as dexterous in practice as you think it will be when you are mouse shopping lol.
https://preview.redd.it/uf4ijlc4s67g1.png?width=1080&format=png&auto=webp&s=dd4113c34e90d806de45db630f3c49d37347efdd I was also afraid of buying a mouse with too many buttons because I thought I’d get confused with all those identical 12-button grids, but I ended up getting the Redragon Aatrox and I’m loving it. It has two big side buttons that I use for important emergency actions, and below them there are two horizontal rows of smaller buttons that are slightly angled, so they feel like two separate groups. Just sliding your thumb over them, you instantly know which button you’re pressing. You can also bind scroll up and scroll down as hotkeys, which helps a lot. Not sure if there’s a wireless version though.
Ditto on Redragon. It’s not terribly well built and downloading the drivers/software feels like I’m downloading something dodgy but it works and you can’t fault the price.
RedDragon is a brand that I bought from after my Logitech G604 started falling apart. The mouse is a little clicky on the button press compared to the Logitech, but I've quickly gotten used to it. The M811RGB-PRO was my replacement, ymmv. When it comes to MMOs (and other games) I use a Logitech G13. Alas no longer on sale, but the hand is well supported at the wrist and it has a thumb joystick. Four fingers rest on the most used buttons, and I set up nearby buttons that are slightly less frequently used. Here's an (old) sample layout that I mocked up to show the idea: the red keys are where you rest fingers and the blue are easiest each. Yellow are for when you need something and movement is not a contributing factor. https://preview.redd.it/nvykk7a7vclf1.jpeg?width=1006&format=pjpg&auto=webp&s=d2fd80b13c879c82967a31e4879fd5798e87bbbd

Logitech G
G600 MMO Gaming Mouse
Customizable MMO workhorse, durable, but discontinued and pricey.

VXE
R1 Series
Budget king: lightweight, great value, long battery life.

Hitscan
Hyperlight
Ultra-light (39g) for small hands; sensor is outdated.

Razer
Viper V3 Pro
Adaptable shape, optical clicks, but scroll wheel malfunctions.

Logitech G
G502 HERO High Performance Gaming Mouse
Durable, heavy workhorse with free-spin scroll; prone to double-clicking.

Ranked #1
Hitscan - Hyperlight

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Teevolution - Terra

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Razer - Viper Ultimate

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ROCCAT (Turtle Beach) - Kone Pro

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Logitech G - G600 MMO Gaming Mouse

Ranked #1
Razer - Naga Trinity