Axis & Allies  vs Power Grid

There are 3 different ground units, 3 different air units, and 5 different sea units you can build, as well as different support structures. Because each piece is different, the leaning curve can be large...but it forces you to be strategic and think about unit counters, which often ends up having a good blend of units

There are about fifteen different version of Axis & Allies, ranging from 1940-42 with 1st and 2nd editions of each to Pacific and Europe editions.

The concepts are pretty easy to grab a hold of (buy power plants, connect different cities together, buy resources for your power plants, then make money and repeat). Each step has strategy involved with it - when you buy power plants you want to diversify from others as resources more in demand cost more - when connecting cities you are looking at pricing but also blocking other players off - you can buy extra resources to boost the price on other players, or buy the bare minimum for that turn etc etc.

You know those games where one player has a great start, and nobody can even dream of catching up? That doesn't happen in Power Grid. It balances itself out - the player currently winning goes first when buying power plants (they get only the current selection), and they build new cities last (worst selection) and pay the most for raw materials.

While the game punishes (at least in a way) the leading player, it helps to balance games and make them more fun overall. In addition, you can strategically not build more cities and hold yourself back if you need the advantage.

There is almost no randomness involved in the game, making achieving mastery of the game about understanding your opponents' plans and working around them.