I hope either TGS or psx

Hopefully, but probably not. TGS is a big show for Japan, but I think a large amount of From's game sales come from outside Nippon. Sony does have 3 more game conferences this year, however, so a new From announcement coming relatively soon is not out of the question. I could see one in December, perhaps, at PSX. 

They are "officially" supporting the Switch at this point with nothing to show. Would love to see the Dark Souls Trilogy come out on Switch -- an exclusive in the vein of Bloodborne is too much to ask, I'm sure.

Give me bloodborne 2, you sons of bitches. I'm finally close to finishing the first and I want MORE.

Oh yeah, I forgot that they are one of the official supporters of the Switch.So if nothing happens in TGS, its always possible that something pops up on a Direct.I mean,s its pretty unlikely, but the possibility is there,.A Dark Souls trilogy being announced at a direct could make for a bigger splasch than it would make at TGS for instance.I mean, I think.

I bet it will be another new IP that's an RPG or of the souls genre.

Yes, they are mentioned like official supporter for Switch so I expecting to see from them some announcement in some point, and I would just love to see DS Trilogy on Switch, but if would Nintendo paid them to make a exclusive game in the vein of Bloodborne, that would be also great. At end I would love to see anything in the vein of DeS/DS announced for Switch.

the wait is almost over

They have to show something, surely. Nothing for over a year for a company with loads of employees, owned franchises and good relations with multiple publishers.

What do we know they are working on?

I don't expect fromsoftware for TGS for Sony or TGS generally.
But if they are it will not be Soulsborne. It could other IP like armored core.