In '
The Ashley Book of Knots' that one is actually called 'the crown and diamond'. I finish the ends of the paracord by pulling out about 1/4" worth of the inner strands, trim those with scissors, pull the outer sheath back down, then a quick heating/melting of each end with my lighter and crimping flat with my hemostats, for already gutted paracord just melt/crimp. If you don't have hemostats, you can use a variety of pliers with toothy grip patterns, or pinch/roll the melted ends with knurled sections of tools or pens...
There's a vast selection of online vendors, distributors, & individuals to source for accessories, plus ebay and amazon, and you may find some things in the buy/sell/trade section of the forums. Some local brick and mortar sporting goods stores, bait & tackle, hardware, Army/Navy surplus, Walmart and craft stores carry useful bits and pieces as well.