Nicely fitting bridge pins can make a noticeable improvement to the sound and appearance of a guitar. I sell two ranges - 5 degree taper pins fit most modern acoustic guitar bridges, whilst 3 degree are preferred by some high end luthiers and were usual on pre-2002 Collings and pre-1994 Martins.
I also have some oversized pins, and have some skinny (.203") 3-degree pins suitable for a wide range of budget and mid-price Far Eastern guitars.
Both slotted and unslotted versions are available in some designs. Slotted pins are more commonly used, but unslotted are suitable where the bridge is slotted to receive the string. Some luthiers and players believe that by slotting the bridge and using an unslotted pin you create greater coupling between the string, pin, bridge plate and soundboard, which improves tone. Others are less convinced!
Ebony and bone are old favourites. Buffalo horn provides the density of bone but 'in black.' Snakewood is a beautiful wood which originates mostly in Suriname, South America. The specific gravity is around 1.2, making it one of the world's hardest woods. It's ideal for bridge pins.