I have done a bit of reading on his tactics and the ability to adapt is what excites me most.
Playing a base formation of 4-2-3-1 or 4-4-2 seems to be the most common but he has also played 4-1-4-1 and 4-4-1-1 depending on the situation. He changes the tactics to create overloads in attack and to solidify the team defensively dependent on the opposition and even more granularly, during transitions (i.e. we might have one or two formations going forward and a different one going backwards).
I also like how the team, despite the formation, works as a unit to compress the opposition when playing without the ball - something that would have helped us in games where we have been overrun by inferior teams this season. A high defensive line, the whole formation shifting width ways, closeness between all 10 outfield players, trigger points on who and when to press; everything has a purpose and a plan. I can't wait to see this team play with an identity again.
I've added some links below that are interesting reads, but also a video where the man himself describes it so well.
Some links to reads:
https://totalfootballanalysis.com/team-analysis/villarreal-202223-scout-report-tactical-analysis-tactics
https://themastermindsite.com/2020/11/14/unai-emery-villarreal-tactical-analysis/
https://www.coachesvoice.com/cv/unai-emery-psg-arsenal-villarreal/
This video about Sevilla tactically defeating Liverpool is pornographic: