Greatswords and only greatswords?
The legendary Incinerator dagger and the mystic forge exotic Firebringer sword are probably the most burny and shiny weapons for those types. You could check the Flame and Molten set skins though they have subtle particles at most. Glyphic set would have some easily affordable particles.
Corrupted Shard (dagger), Corrupted Blade (sword) and Infinite Light (sword) also come to mind. Note that with many of the particle heavy weapons you can’t know what they really look like by using preview. Look for screenshots and videos or try to obtain them in structured pvp.
Also make a note to check out the Priory weapons since their green glass/crystal parts don’t show up in preview. Cultural sets like sylvari plant weapons also bring variety. Asura have the equivalent of the glowy pvp peacemaker set.
(edited by Ksielvin.1587)