Is there any computer program with AI capabilities (the generative ones seen in ChatGPT; onlineText-to-Picture generators, etc.) that is actually standalone? i.e. able to run in a fully offline environment.

As far as I understand, the most popular AI technology rn consists of a bunch of matrix algebra, convolutions and parallel processing of many low-precision floating-point numbers, which works because statistics and absurdly huge datasets. So if any such program existed, how would it even have a reasonable storage size if it needs the dataset?