For disk controllers (called Host Bus Adapters), I like the LSI controllers. If you don’t need SAS3, then used SAS2 controllers are very affordable and will permit you to use SAS or SATA drives. I have been finding new SAS drives are often cheaper than SATA at the same capacity since they can only be used in servers (with SAS HBAs). Avoid the MegaRAID controllers as they are RAID controllers and not just HBAs and do not work well with ZFS. I also make sure I use IT firmware (most used HBAs from reputable sources will already have IT firmware, if not it is fairly easy to do, it is just an extra couple steps).
Here is one example https://www.serversupply.com/CONTROLLERS/SAS-SATA/HOST%20BUS%20ADAPTER/LSI%20LOGIC/9207-8I_287587.htm but I have seen them as low as $30.
Avoid at all costs SATA enclosures with port multipliers. Multiply your problems with SATA Port Multipliers and cheap SATA controllers
SAS bus expanders are fine.