Is there a website or otherwise maintained list of talks regarding mathematical optimization? This would be a big help for the community it seems. I'm most interested in those relating to integer programming.
In terms of conferences, the Egon Balas Symposium in 2019 contained numerous talks on mathematical optimization. For integer programming specifically, it includes
the Geometric Firefighter Routing Problem (Cid de Souza)
the Graphical Traveling Salesman Problem (Neil Simonetti).
There are these great introductory lectures on coursera (not sure if that qualifies for your question as they are not research talks):
If you are into research seminars / current topics, Aleksandr M. Kazachkov has compiled an interesting list of online seminars on optimization.
For what it's worth, the 2th part of my talk at Devoxx Morocco, explains Tabu Search, Simulated Annealing and other (meta)heuristics.
Check out Gurobi's materials: https://www.gurobi.com/resources/
You can find an introductory course of Convex Optimization from Stanford University taught by Professor Stephen Boyd, in this link.
Check out the following link from the Simons Institute (they had a program on bridging continuous and discrete optimization in 2017).
Also the Hausdorff Institute had a trimester on combinatorial optimization in 2015.