Grease from cooking meats like bacon, ground beef, etc. become solid at room temperature. There are many things that are already solid and stay solid at room temperature though, like most things in a pantry, furniture, etc. This is a vague question.
Copper is a solid at room temperature.
Actinium is a solid at room temperature.
Titanium is a solid at room temperature.
Vanadium is a solid metal at room temperature.
Boron is a solid at room temperature
At room temperature and standard pressure the element Boron is a solid.
Magnesium "MG" is a solid at room temperature.
Yes, carbon is a solid at room temperature.. Elemental carbon is a solid at room temperature
The element, Selenium, is a solid at room temperature.
iodine is solid at room temperature
Sucrose can be both solid or liquid. At room temperature, however, it's a solid.
At room temperature, magnesium chloride is a solid.