Swarms are making a comeback in my local meta.

They come in the standard tie swarm variety.

What's the common way to defeat large swarms these days and what would make for a tournament level list that has to keep an eye out against swarms.

Well, I'm sure assault missiles and ion torpedoes are quite effective against swarms, if you can find a good way to consistently land hits with them (I hear Guidance Chips is a must-have for this purpose)

Ruthlessness seems to work quite well too.

Assault missiles