@sarahtinson You know, it’s interesting to think about this; not all cards in the center need to be programmed.
There are a few types you can create without programming, like the no-code ones, and one of them is based on reports. Imagine creating a single-object report, say line items, and associating it with a company card.
The company card automatically adds the company filter, giving you a quick report with all line items related to that company. You can do similar things with deals and other objects associated with the company.
Why not give it a try and see if it meets your expectations? It’s much faster to test this than developing a custom card.
And then, of course, with development, you’ll have many more possibilities opening up before you. In the end, it’s can a good path to take, but perhaps you can start by taking those first steps with the no-code functions at hand.