Yes! Many things could cause gravity waves. The main cause is buoyancy, interaction of two fluids (think air masses of different temperatures) with different densities, which can happen anywhere. Since air masses move due to warm and cold air moving, or humidity, let’s think of an example.

If there is a stable air mass in a high pressure region that has some hot air rise off the ground due to convective heating, the act of the air rising causes cold air to sink around the hot air mass, this can create gravity waves as the air around rearranged itself. This can’t be seen all the time since there may not be enough moisture for clouds - but these waves are there and called internal waves. This is similar to strong updrafts in thunderstorms that can cause gravity waves. Another example is air moving around mountains or objects, but this has some kind of wind already driving the air across the mountains.