Other molecules like fullerenes?
Cool question! Always stay curious!

A while ago, I had a similar question that started it's journey with silicon, being of similar bonding capability to carbon. However, over the course of my research, I realized that silicon was just too low on the periodic table (and therefore much heavier) to be so extremely stable in such a wide variety of forms such as fullerenes and long, complex hydrocarbons.

However, my search was not in vain. I stumbled upon Boron Nitride, an isoelectronic analog to carbon graphite. Many different compounds have been synthesized from boron nitride, consisting of a wide array of fullerene analogs, such as Boron Nitride Nanotubes, or BNNTs, which by themselves have plenty of applications. For example, paper products made from these nanotubes are highly flame retardant, as is shown in the image below:



The trick is that $\ce{B-N}$ has very similar properties to $\ce{C=C}$, with very little difference in molecular weight, and so many analogous compounds can be built using either monomer. However, boron nitride is different enough to have unique applications in certain areas. Cool, right?