dont forget graph theory. FB caught me off guard on a takehome project which involved contact tracing (very timely in 2021)
Dyjkstra's algorithm (spelling?) and backward tracing through graph nodes
Those two algorithms are the workhorses of graph algorithms.
Advanced graph algorithms include Dijkstra's algorithm, Minimum Spanning Tree, Strongly Connected Components, among others.
In addition, dynamic programming (DP) also shows up as a more advanced algorithm/technique in high-level interviews.