TL;DR: Pick one of These

$14 Pentel GraphGear 1000 (https://amzn.to/3b9r9Ml) (only $10 without the extra erasers)
- This is what I actually got and so far so good
  (though I think I would have preferred the 0.5mm to the 0.7mm)
- 15k nearly all-5-star reviews, and Retractable!!
$8 Amazon Basics Mechanical Drafting Pencil (https://amzn.to/3hkrIHh)
- I plan to get the 0.5mm to try this out
- Retractable!!
$25 rOtring 600 (https://amzn.to/3tnKyzh) (non-retractable) or rOtring 800 (https://amzn.to/2QT2apQ) (retractable)
- A strong recommendation, but I fear the non-retractable version may not serve me well...
  (and the 800 is out of my $30 price cap)
- (that's the letter 'O', btw)
$20 for 12 Zebra M-301 (https://amzn.to/3emlm86)
- For when any pencil that works is more important than a single pencil that works...
$959 MontBlanc Leonardo Sketch (https://amzn.to/3h824Fe)
- For the times when nothing less than opulence will do. :D

I also saw recommendations for the Pentel Quicker Clicker (https://amzn.to/3us2B94), GraphGear 500 (https://amzn.to/33sAr1z), and $20 Caran D’ache 844 (https://amzn.to/33jryHV), but... I have no faith in non-retractables.

What to consider

Do you want it retractable?
Would you prefer a metal barrel?

Honorable Mentions

Normally those "Top 10" style sites are spam garbage, but this one seemed like maybe real humans were involved, or at least some of the recommendations correspond with what I got from real people:

https://www.gearhungry.com/best-mechanical-pencils/

Backstory

As a kid I though mechanical pencils were the bees knees - but since I never had one that lasted for more than about 20 clicks without breaking (or rather, without then breaking the lead every 3-4 clicks), I stopped using them entirely.

However, I started playing D&D recently and realized that perhaps about the only thing I trust less than a mechanical pencil is, well, any sort of Adobe product on my computer.

So instead of using the really cool automated character sheet that only works with Adobe Reader X-whatever and risk ruining and having to completely reformat my nice, new Macbook Air M1, I decided to go on a completely different quest to find a pencil that I liked to keep my character sheet up-to-date.

And guess what? It darn sure wasn't going to be a BIC Wood-Cased!

And so I took to Twitter (https://twitter.com/coolaj86/status/1387975667799662596) and Facebook (https://www.facebook.com/coolaj86/posts/10159205210800502), but exercised prudence in intentionally avoiding reddit (https://twitter.com/gabegundy/status/1388004072888754181).

This is my captains log such that my struggle is not lost to the sands of time...

By AJ ONeal

Did I make your day?