No, you're not late to the game. You just missed out on some good keycap sets, though. Recent group buy sets have been: Ragnarok, Cream Cheese and Green, and Red Alert 2.0. 7bit's "Round 4" is going on now with several options, Spherical, Round 3, Retro, and Noir, but it has been ongoing for about a year, and there is always some confusion involved. There is a group buy going on right now for the Sanctuary set. And soon Keyboard Story should have Cream Cheese and Red, CC&Blue, and another CC&Green.
You should also be on the lookout for sets of doubleshot keys made by Cherry Corp. White on black sets are fairly common, in varying conditions, and black on white sets are available from time to time. You might need what is called a "moogle" kit to make those sets work with a modern keyboard, though.
Dolch sets and WYSE sets are also available, if somewhat harder to find.