simplicial sets, filling conditions: Kan complexes, Quasi-categories, (various flavors of) fibrations.
The language of higher category theory: mapping spaces, functors, , the infinity categories of spaces and of categories.
Limits and colimits, adjunctions, Kan extensions, Yoneda Lemma.
Presentable infinity-categories of
Examples: infinity categories and topology, derived infinity categories, infinity categories of sheaves.