I haven't ordered any recently, so I don't know if you can get these anymore. Generally Intel nics are supported, but there are sometimes problems with the newest chipsets. Anyway, I'm running these personally in several boxes, so I'm sure they work with pfSense.
Intel PWLA8492MT Dual 10/100/1000 PCI/PCI-X
Intel EXPI9402PTBLK Dual 10/100/1000 PCI-e
These may be the low-profile numbers, but IIRC, they came with both brackets.
If you don't need GB, check ebay for used dual-port Pro100 cards.