What is a good source for quality cable ties or zip ties. In particular I want ~15-inch heavy duty ties. I have searched the internet and everything I find is non-US made and gets questionable reviews.

Panduit is another. Not sure where they're made these days, but they have always been very good.
Thomas&Betts ty-rap.
The "ty-rap" brand is what we use at work. They have the metal tab in them and you never get pull outs. Made in USA.
Yep. Nuthin' but genuine metal toothed T&B Ty-Rap for me, thanks...
...Zipties are one thing I will not buy from HF.
I've used non-metal ones for years. Never had one fail. Hope they meet your expectations.Just ordered these T&B. I would have preferred the metal tab ones if they had been long enough.
https://www.amazon.com/dp/B0018O3O4G/?tag=atomicindus08-20
Just ordered these T&B. I would have preferred the metal tab ones if they had been long enough.
https://www.amazon.com/dp/B0018O3O4G/?tag=atomicindus08-20
Just received these. Look good but are Made in Mexico. Hope they hold up.