SD 1.5 is a base model that is used for fine-tuning. QLora is a technique for fine-tuning with less hardware and time. People distribute the resulting QLora files, which you can load alongside the base model. A1111 and ComfyUI are tools for coordinating the inputs, models, outputs, and post-processing. ControlNet and AfterDetailer are specific projects that would plug in to A111.