Here are the stores I know of so far where stim toys and stim jewelry are made and/or sold by autistic people. I invite people to add any others they may know of and I’ll update the list. 

Stimtastic - link 
Details: Sells a wide variety of stimmy things. Donates 10% of profits to autistic orgs or to autistic individuals. They have a program for free or subsidized weighted blankets for autistic people who cannot otherwise afford them: link. 

A Sense of Self - link

Fuzzwumpet - link

WeirdFaeles - link
Details: Witchy chewable jewelry! 

Spacerobot Studio - link 
Details: Visual stimmy necklaces. Donates 10% of proftis to ASAN. Also sells nice communication and neurodiversity necklaces. 

Oakflower Design - link

Ruth/doo/dle - link
Details: Sells chewable jewelry and monthly sensory boxes (and usually has one giveaway on tumblr too!). Also sells autistic pride jewelry and buttons. 

Fabulous Fidgets - link

AutisticRabbit - link
Details: Custom, affordable weighted blankets!

GeckoHQ - link

Sister Cat Blankets - link

Pretty in Pi - link

Shop Ca5ey - link
Details: Very cute unique weighted stuffed animals, like hedgehugs and rattlesneks. 

Mow Liao Crafts - link
Details: Versions of Fidgetland’s fidget toys exclusively for people within the UK.

Papercraft Hugs - link

(Bonus: Here are a few ADHDer-owned stores for fidget toys
Fidgetopia - link
Fidgetland - link 
Details: Donates some of profits to an org supporting autistic/adhd-er kids. I don’t know how good this org is though.)