For a current list of the gears look at hedgewars/uTypes.pas at
the TVisualGearType enumeration. http://code.google.com/p/hedgewars/source/browse/hedgewars/uTypes.pas#108
{{{
TVisualGearType = (vgtFlake, vgtCloud, vgtExplPart, vgtExplPart2, vgtFire,
            vgtSmallDamageTag, vgtTeamHealthSorter, vgtSpeechBubble, vgtBubble,
            vgtSteam, vgtAmmo, vgtSmoke, vgtSmokeWhite, vgtHealth, vgtShell,
            vgtDust, vgtSplash, vgtDroplet, vgtSmokeRing, vgtBeeTrace, vgtEgg,
            vgtFeather, vgtHealthTag, vgtSmokeTrace, vgtEvilTrace, vgtExplosion,
            vgtBigExplosion, vgtChunk, vgtNote, vgtLineTrail, vgtBulletHit, vgtCircle);
            vgtSmoothWindBar, vgtStraightShot
}}}