So what game, not designed by DXV and not a ripoff, has a known random component subset? 
The Chaos Pack for We Didn't Playtest This At All has a dozen or so cards. Each is essentially an extra rule for the game. The intended use is to have one or two randomly selected and put into play for a game and then replace them afterward.
Mario Golf has a mode called Club Slots where before each hole the players use a slot machine to select what clubs they'll be allowed to use. From the usual 14 you only get 3 plus your putter.
I suspect one of the reasons that the mechanic is so uncommon is that adding components to a game increases it's cost, so adding components that won't always be used is harder to justify.