What brand are you most loyal to?

I stan no brand! I will always jump ship if they change the product in a worse way or something better comes along. I have no consumer loyalty whatsoever. It's more the opposite, some corporations I refuse to give money to because they are worse-than-regular-capitalism bad like have nazi owners or such.
I do have current favorites though like La Roche-Posay is making some killer peptide face cream that smells nice!
- Same, brand loyalty is a serious turn-off and advertising makes me less likely to want to buy someone's product.
  That said, I have been happy with TomboyX and Bonds for making bras and tucking panties that actually fit a weird enby like myself.
  I'd also be remiss if I didn't mention my favorite furry perfumery, Huff Aromas. https://huffaromas.com/, the only place to buy scents like "werewolf femboy pheremones", intersex cat-person in heat", "elephant dad stank", "hyena mommy pits", or "buff dragon's jockstrap".

This might be a bit of a stretch because it’s not a “brand” but…
Linux! I uninstalled windows almost 2 years ago to help me kick a bad gaming habit, and while I can appreciate the design of macOS and was a macOS user for YEARS before windows, I just can’t leave Linux now. Once I felt freedom it was impossible to convince myself to climb back into the ad filled box.

I buy a lot of my clothes from Pact, esp. undies and bras - I like that most of their stuff is cotton and they are so eco-focused. Not sure it's strictly brand loyalty, but in practice I don't buy those things elsewhere.

Clover Amour crochet hooks! I've tried other brands because they looked great but nothing ever compared to the smoothness of the clover hooks!

Leolines! Expensive, but worth it if you're a trans gal looking for comfy panties.
Their bras are nice because they're proportioned for trans girls, but those might be easier to find elsewhere. I only own one bra atm (not a daily wear yet...)
- So, I get that Leolines is all made by one person, and she's doing us all a really great service, but I was disappointed by the quality after buying four and having the threads give out for three in the span of a few months. I'm still a novice steamstress, but I feel like splitting the most vulnerable point of the garment into two pieces of fabric (right where the tuck is) might be a design flaw.
  Overall, I personally prefer TomboyX. The stitching method is better and has stood the test of time for me. And PAKA Apparel undies actually tuck surprisingly well too, despite not being made for trans women.

Caran d'Ache Pablo color pens. My mom got a big set of them when I was little and now I won't use any other coloring pens for my art.

King Arthur Flour. Better quality than store brand and employee owned.
- Oooo you got there before me! It's my go to for these types of questions XD
  It's such good flour! Even my most finicky cookies do better on it.
  Keeping in the vein of food, Penzeys spices is my go to spice people. Great spices. Great public outreach stuff? Love their emails.

Hi-tec is the only brand I've found that makes quality vegan hiking boots at a good price. I'm on my third pair.

Zebra pens. The F-301 is the best pen ever made, ever ever. The pink barrel one is my favorite, because duh it’s pink. I like them so much that I have close to 30 extras just in case.
- I switched to fountain pens last year, the chinese brand Hong Dian makes some pretty decent ones at reasonable prices and Monteverde's 2019 Special Edition teal has been my favorite ink so far.

My community is lucky to have a local grocery store, and it's a co-op, so I'm very loyal to it.
Otherwise, it's hard to be a loyal customers when so many brands change for the worse. I did get a "Hey, I use their soap!" moment after seeing Dr. Bronner's post about Pride and link to multiple pro-trans organizations they donate too, especially after so many brands have backed out this year. That was nice.

Most of this stuff is probably in creative tools/technology side. Nikon cameras, Asus computers, Wacom tablets, stuff like that. Because for these purposes I prefer to buy known-good tools that I'll be able to use for a decade or more.