\cap \(\cup\) \cup \(\in\) \in \(\subseteq\) \subseteq \(\subsetneq\) \subsetneq \(\notin\) \notin \(\bigcup\) \bigcup Other You might need \qed, \qedsymbol, \blacksquare for proofs. It is the Tombstone \(\blacksquare\) I’ve recently needed \(\dots, \ddots, \vdots\) (\dots, \ddots, \vdots) for a visualization in a matrix. Note that you can write … instead of \dots,