This question is a bit broad in terms of the sheer amount of chemical compounds and mixtures that are liquid at room temperature. Examples include:
Acids, bases, many hydrocarbons (e.g. hexane) and many more
Crude oil, aqua regia and many more
In terms of elements, there are only two that are liquid at room temperature (say about 20 °C or 293 K):
Francium, cesium, gallium and rubidium are close, with melting points at 300 K, 301.59 K, 303.3 K and 312.46 K respectively.
LennTech provides a list The elements of the periodic table sorted by melting point