In roughly reverse chronological order:

For a seminar on the relative Langlands program, organized by Gyujin Oh:

• Hyperspherical varieties
• Dual groups of spherical varieties

For a series of seminars loosely around the topic of p-adic modular forms and Hida theory, primarily organized by David Marcil:

• Hilbert modular varieties and Hecke operators
• Higher Hida theory (slides)
• Lambda-adic Galois representations

Assorted other seminars:

• Introduction to prismatic cohomology (slides), for a virtual seminar on prismatic cohomology organized at UCLA
• The Tannakian formalism and the motivic Galois group, for a seminar on motives, standard conjectures, and Weil cohomology theories organized by Morena Porzio
• Taxicab numbers, for the Undergraduate Mathematics Society at Columbia
• Hilbert schemes, for a seminar on knot homology and derived affine Hecke algebras, organized by Zoe Himwich, Davis Lazowski, and Sam DeHority
• Hodge-Tate and crystalline comparison theorems, for the Spring 2021 STAGE seminar on prismatic cohomology