Offering a few things for free could be a good way to get noticed, but it doesn't always translate into sales later down the road, unfortunately. Common household items are not typically big sellers unless you have a really big portfolio of them with high-quality modeling and textures. However, if your models are really well done, and your prices are competitive, you could make it work for you. Architecture could do ok if, again, your work is high quality and modeled in such a way that it's versatile and useful for more than one purpose (ie, it could be used in-game or for cinematics). Sci-fi will obviously sell, especially if it's something people recognize (just look at the baby Yoda's out there) and high quality, or if it's something unique and cool that catches people's eye.
I recommend to just do what you do best, and do it as well as you can. Focus on growing your portfolio steadily but don't sacrifice quality. I see people doing very well with less than 12 models (it's rare but can happen), while there are some others who struggle to get by with a portfolio of 100+ models. Quality first, quantity second.