The most common thing you see shared is something called IP which does mean intellectual property, but in this context you can think of it like buying ICs that you integrate into your design (ie you wire them up). You can also get Verilog, but that is usually used for verification instead of taping out the peripheral. This is because the company you buy the IP from will tape out the design for a specific node in order to guarantee the specifications. Examples of this would be everything from arm cores to uart and spi controllers as well as pretty much anything you could buy as a standalone IC.