Anyone know of any regionals in SEA other than Horizon Air?

I know Skywest flies out of SEA. I don't know if that helps?
fbh

If you're just asking what regionals fly to Seattle:
Horizon
Skywest
Mesa
ExpressJet
AC Jazz

If you want to be based in Seattle, Horizon is about it.

Skywest has a PDX base, which isn't too bad of a commute. Hell, you could drive it if you had to. Horizon does have a Seattle base, but I believe it's pretty senior. My understanding is most new folks go to PDX.

Also, I believe Kenmore Air does a land-base operation with Caravans out of Boeing Field, serving the San Juans and that area.

Actually, I'd have to say PDX is more senior simply because the RJ base is there. Depends what airplane newhires get assigned.

Empire but use caution.