This is a list of (hopefully) all gear types, along with a short description and the interpretation of the gear’s tag (see `GetTag` and `SetTag` in [LuaAPI]).

Please note this list is still mostly TODO.

|| Gear type || Description || Meaning of tag ||
|| gtATStartGame || TODO || TODO ||
|| gtATFinishGame || TODO || TODO ||
|| gtWaterUp || If added, water will rise. Coordinates are ignored. || Number of pixels the water still has to rise. By default, the tag will have an initial value of 47. The gear will be removed when the tag equals 0. ||
|| gtAddAmmo || TODO || TODO ||
|| gtGenericFaller || TODO || TODO ||
|| gtTarget || a target, useful in target practice missions. || TODO ||
|| gtCase || an ammo, utility or health crate || TODO ||
|| gtExplosives || TODO || TODO ||
|| gtFlake || TODO || TODO ||
|| gtFlame || a flame || between 0-32 (TODO) ||
|| gtGrave || a grave from a dead hedgehog || TODO ||
|| gtHedgehog || a hedgehog || used for animation. 0 = no animation plays. Other value: animation plays ||
|| gtRope || a rope || TODO ||
|| gtTardis || a !TimeBox || TODO ||
|| gtParachute || a parachute || TODO ||
|| gtJetpack || a flying saucer || TODO ||
|| gtGirder || a girder || TODO ||
|| gtTeleport || teleportation || TODO ||
|| gtSwitcher || switch hedgehog || TODO ||
|| gtPortal || a portal from the portable portal device || TODO ||
|| gtLandGun || the land spray tool || power of land spray (0-10) ||
|| gtBee || homing bee || wheather the bee is underwater (0 = no, 1 = yes) ||
|| gtFirePunch || shoryuken || Y coordinate ||
|| gtDrill || drill rocket || used for drill strike. If 1, then first impact occoured already ||
|| gtFlamethrower || a flamethrower || power of flamethrower (0-10) ||
|| gtResurrector || resurrection || TODO ||
|| gtAirAttack || The airplane of an air attack || direction of airplane (-1 = left, 1 = right) ||
|| gtCake || a cake || A timer for the final “sitting down” animation. It starts at 0 and will be destroyed when it reaches 2250. ||
|| gtRCPlane || a RC plane || dX speed??? ||
|| gtBirdy || Birdy || facing direction (left = -1, right = 1) ||
|| gtEgg || an egg from birdy || TODO ||
|| gtGrenade || a grenade || TODO ||
|| gtShell || a bazooka shell (projectile) || TODO ||
|| gtShotgunShot || a shot from a shotgun || TODO ||
|| gtPickHammer || a pickhammer || TODO ||
|| gtMine || a mine || TODO ||
|| gtDEagleShot || a shot from a desert eagle || TODO ||
|| gtDynamite || a dynamite || TODO ||
|| gtClusterBombe || a cluster bomb || TODO ||
|| gtCluster || a cluster from the cluster bomb or the mortar || TODO ||
|| gtShover || used by baseball bat (TODO) || TODO ||
|| gtAirBomb || a bomb from the air attack or the RC plane || TODO ||
|| gtBlowTorch || a blowtorch || TODO ||
|| gtMortar || a mortar || TODO ||
|| gtWhip || a whip || TODO ||
|| gtKamikaze || an ongoing kamikaze || TODO ||
|| gtSeduction || seduction || TODO ||
|| gtWatermelon || a watermelon bomb, still intact || TODO ||
|| gtMelonPiece || a cluster from a watermelon bomb || TODO || 
|| gtHellishBomb || a hellish hand-grenade || TODO ||
|| gtBallGun || a ballgun || TODO ||
|| gtBall || a ball from the ball gun || Color: 0=red, 1=green, 2=cyan, 3=yellow, 4=violet, 5=pink, 6=orange, 7=lime, 8=white ||
|| gtSniperRifleShot || a shot from the sniper rifle || TODO ||
|| gtMolotov || a molotov cocktail || TODO ||
|| gtPiano || piano from piano strike || TODO ||
|| gtGasBomb || an old limburger || TODO ||
|| gtSineGunShot || a shot from the sine gun || TODO ||
|| gtSMine || a sticky mine || TODO ||
|| gtPoisonCloud || a poisonous cloud, makes hedgehogs sick on contact || TODO ||
|| gtHammer || a hammer || TODO ||
|| gtHammerHit || TODO || TODO ||
|| gtNapalmBomb || a bomb from the napalmn strike, will burst into fire || TODO ||
|| gtSnowball || a mudball || TODO ||
|| gtIceGun || a freezer || TODO ||
|| gtKnife || a cleaver || TODO ||


Here is an excerpt from the Hedgewars source code:
{{{
    TGearType = (gtFlame, gtHedgehog, gtMine, gtCase, gtExplosives, // these gears should be avoided when searching a spawn place
        gtGrenade, gtShell, gtGrave, gtBee, // 8
        gtShotgunShot, gtPickHammer, gtRope, // 11
        gtDEagleShot, gtDynamite, gtClusterBomb, gtCluster, gtShover, // 16
        gtFirePunch, gtATStartGame, // 18
        gtATFinishGame, gtParachute, gtAirAttack, gtAirBomb, gtBlowTorch, // 23
        gtGirder, gtTeleport, gtSwitcher, gtTarget, gtMortar, // 28
        gtWhip, gtKamikaze, gtCake, gtSeduction, gtWatermelon, gtMelonPiece, // 34
        gtHellishBomb, gtWaterUp, gtDrill, gtBallGun, gtBall, gtRCPlane, // 40
        gtSniperRifleShot, gtJetpack, gtMolotov, gtBirdy, // 44
        gtEgg, gtPortal, gtPiano, gtGasBomb, gtSineGunShot, gtFlamethrower, // 50
        gtSMine, gtPoisonCloud, gtHammer, gtHammerHit, gtResurrector, // 55
        gtNapalmBomb, gtSnowball, gtFlake, {gtStructure,} gtLandGun, gtTardis, // 61
        gtIceGun, gtAddAmmo, gtGenericFaller, gtKnife); // 65
}}}
For a current list of the gears look at hedgewars/uTypes.pas at
the TGearType enumeration.
http://code.google.com/p/hedgewars/source/browse/hedgewars/uTypes.pas#92

Note: gtBomb and gtShell were named gtAmmo_Bomb and gtAmmo_Grenade before 0.9.14