I think it’s pretty safe to assume that ICANN will eventually approve a second round of new gTLD applications. I don’t know when round 2 will happen, but if I was going to place a wager, I would bet there will be at least one subsequent round of applications. I was thinking about what types of new extensions might make up the applications since most of the “good” ones are probably already assigned or awaiting approval.
I had a thought that some new gTLD registries might apply for the plural or singular version of the registries they already manage. For example, perhaps Uniregistry could potentially apply for .Links or the .Club registry could apply for .Clubs. It certainly wouldn’t make sense in many cases, but I could see a few reasons for it.