Anyway to some diminishing returns.
I mentioned Terraforming Mars, as it was in my mind. The first player gets more points than the second for each milestone. It's not unique to this game by any means, but it's a good example.
Dominion and many other deckbuilders in many ways feature a combination of opportunity cost and diminishing returns. The Victory Point cards are limited in quantity, but they are part of the deck, so early purchases can limit later ones. For the unfamiliar, each player starts with a small standard deck(identical, and usually 10 cards), and add to it throughout the game.
War games also have a version of diminishing returns in that there's limited benefit to adding more units to a conflict or point within a conflict. The general attack ratio for victory is 2:1 in straightforward military conflicts. Past 3:1 there's limited benefit. Some wargames model this through number of dice, and there's a target number/symbol.
Games like X-Wing add defense dice, and Warhammer has a save roll against death. Warhammer's is less likely to be overrun by sheer number of dice, but both are overwhelmed.
The flipside is increasing cost, and we see this in games with supply/demand mechanics. Power Grid is the key example for this, with prices adjusting for each of a commodity bought. The Korea board even has two markets, and a player may only purchase from one.
Planet Steam also has a supply/demand aspect, with some things becoming unavailable for parts of the game, and market manipulation being a key aspect of play. The below image is mostly on the market.
As usual, these are but a glimpse, and hardly definitive examples, though I hope they are clear. I think next time I might cover incentivizing suboptimal decisions.
When you play Social Justice, the world loses.