A few examples:
"Square": Sabre, PD Reserve, Triathalon (IIRC)
"Tapered/Semi-Elliptical": Sabre2, Safire 1&2, Lotus, Pilot, Fusion, Spectre, Navigator, Silhouette, etc...
"Elliptical/Fully-Elliptical/High-Performance": Samurai, Stiletto, Nitro(n), Katana, Crossfire 1 & 2, Jedei, Cobalt, Blade, etc...
"Cross-braced": Extreme FX, VX, JVX, Xaos-21, 27, Velocity, etc...
"Defies description": Diablo NSCR-2376, SCR-15080