These are the best places to find the best archviz textures.
Two of the most usual phases when we work are modeling and texturing. I do not know how many hours of my life I will have dedicated to both tasks.
Apart from the creation of custom textures, we always look for websites that offer quality textures that can be useful. From my point of view, I do not think it is necessary to have large collections of textures for our architectural visualization work.
Even so, here I leave you a selection of the sites that I consider most interesting.
At the end, you will find a complementary list of websites that offer HDRI images so needed for our work. Another day we will talk about other very important archviz textures in our work: cutout people
As always, I recommend that you do not focus solely on free resources.
Your time is worth much more and the results are usually better with payment resources.