I would like to ask about recent examples, mainly after 2015, where experimentation by computers or other use of computers has led to major mathematical advances.
There are several categories:
A) Mathematical conjectures or large body of work arrived at by examining experimental data
B) Computer-assisted proofs of mathematical theorems
C) Computer programs that interactively or automatically lead to mathematical conjectures.
D) Various computer programs which allow proving automatically theorems or generating automatically proofs in a specialized field.
E) Computer programs (both general purpose and special purpose) for verification of mathematical proofs.
F) Large databases and other tools
Of course more resources (like this Wikipedia page on experimental mathematics) are also useful.