Souls or Soulsborne tbh.
I feel like Bloodborne should get a shout there because it's very different from the Souls games but also extremely similar in a lot of ways, whereas Sekiro feels much more different than Souls or Bloodborne despite also having much of the same DNA.
Elden Ring just straight up feels like Dark Souls 4 (or just a sequel to Dark Souls 2 SOTFS, the now second best one) in terms of pretty much everything but the name and lore, so I don't really feel like it should be included in the naming of the collection of From games.
Plus Souls and Soulsborne both roll off the tongue very well, that isn't really the case when adding Sekiro or Elden Ring to the mix, even if you did just Souls and Elden Ring it wouldn't flow as well as Soulsborne