Euuuuuy gotta look through almost all the news' pictures then xP
I think most, if not all, are returning. Many pictures show quite a bit of old gear. Acouple I remember off hand are the parka and retro glasses, so that's Forge and Splash Mob (I think that new wide red horizontal striped shirt was Splash Mob as well...)
Lemme do a scan through and I'll get back to ya.
OK, list tiem
Forge = Inkling Parka, Blue Sailor suit
Splash Mob = That new red strip shirt that which the gasm mask inkling is wearing in the spawn point pic
Takaroka = Orange Arrow shoes
FireFin = 8 bit Fish Fry shirt
Krak-on = cream basics
SquidForce(of course, derp) = white headband
Rockenberg = Roasted Brogues
Zekko = Green Check shirt
Skalop = Straw Boater
Tentatek(did you really think this brand was going anywhere? of course not) = Tennis Headband, sun visor, c- ya know there was a whole splatoon tweet posted today dedicated to tentatek, there a quite a few examples
Amiibo brand ... of course its back, we're getting new amiibos, after all =p
Brands I did not see in the 2 nintendo direct videos about spla2oon
CuttleGear ( ;_; it'll probably be back for story mode rewards, even if our ol' seadog isn't returning. . . ;_;)
Inkline (I actually saw what seemed to be the short beanie... but it's such an unassuming picec of gear that I wasn't 100% sure of myself)
KOG (I think it's back, it is a nintendo brand for real world jank, so yeah)
The SQUID GIRL (just ask enough and it'll return ;0 )
Zink (not seen, but with all the other returning brands, it makes almost no sense to NOT re-introduce this one)
Famitsu