Haha. Remember when everyone was saying that PS+ was flooded with indies and that Sony should just include Knack. Yeah...
All joking aside, while Knack isn't a great game by any stretch, it isn't a particularly bad one, either. It's main pitfall is that it's totally fine. Almost painfully so.
It's actually an indie game from the EU PlayStation Blog post about this month's games that shuold have you excided, though. Rime is absolutely beautiful, and an an absolute steal for some sum of money that you already gave to Sony months ago.
Oh, and there is of course some stuff for the PS3 and Vita, too, as well as a VR title:
StarBlood Arena (PS Plus bonus – PS VR required)
Spelunker HD (PS3)
Mugen Souls Z (PS3)
Exiles End (PS Vita)
Grand Kingdom (PS Vita & PS4)