2 row, marris otter, maybe some crystal 40 or 60, and the 3C's hops.
Definitely a good list. Here is a little more expanded list:
2 row malt of your choice (l like Marris Otter), lots of it.
Munich Malt - good addition in small amounts to a lot of different styles
Variety of Crystal Malts - 40 for sure, 60 for sure, 20 is good to have also.
Roasted Malts - For darker beers, Chocolate for sure, Roasted Barley, maybe some black patent.
Wheat malt: nice addition to almost any style and the occasional wheat beer is always nice.
On hops, I stock American varieties and English varieties. Depending on what you like, this can vary quite a bit.
Centennial: My go to hop for IPA's, but harder to get these days. Try any good pungent style for most hoppy American styles (Columbus, Simco, Amarillo, others). Do some reading. Stock two of your favorites and you can brew just about anything American.
East Kent Goldings: Good for just about any English style, barleywines, stouts, brown ales, etc. Can substitute other "Goldings" varieties if needed. Challenger is also a good English variety.
Get some neutral bittering varieties for general use and not so much "hop character". This will help to extend your inventory of the American and English varieties that might be harder to find. Some examples: Nugget or Perle (my standard).
If you are limited on inventory, this is a good start and will allow you to brew a good variety of beers. As you brew, you can hone in on which styles you keep returning to and eliminate some of the stock items and add others so that you don't have items that just "hang around" and don't get used.