Secondary professions for a Warrior

Warrior/Ranger

 * The Ranger line offers a few alternative IAS skills.
 * Apply Poison, though effective is energy intensive for a warrior, and requires spending attributes in a line mostly useless for warriors.
 * Anyone seeking to combine these two professions effectively would be better served here.

Warrior/Elementalist

 * Shock can be used as a snare and interrupt, however exhaustion will certainly be felt with a Warrior's low energy pool.
 * Grasping Earth can be used as a AoE snare to keep groups of enemies from kiting as efficiently.
 * The conjure skills, such as Conjure Frost can provide additional damage when wielding an elemental weapon for a very small investment of energy.

Warrior/Mesmer

 * Wise use of Physical Resistance, Elemental Resistance or elemental mantras can add additional survivability to solo or tanking builds. A tremendous boon is that a warrior can constantly maintain the previously mentioned stances without any investment in their attribute lines.
 * Hex Breaker is often useful as a cancel stance and for hex prevention.
 * Web of Disruption can be used as an interrupt in a build with little energy skills.

Warrior/Monk

 * The condition and hex removal skills of the Monk close a critical gap in the warrior skill line. Skills such as Mending Touch, Purge Signet and Empathic Removal are good utility skills.
 * Despite the popularity, Healing Prayers skills are less effective then a warrior's self healing skills, and should be avoided. This is especially true of Mending, which is often considered a laughable build element due to its low healing and high maintenance cost, and the ability to be replaced by the lesser-used Watchful Spirit.
 * One of the few ways to reap the benefit of the Healing Prayers line is to combine skills like Vigorous Spirit with skills like Hundred Blades, but more importantly, Cyclone Axe and Triple Chop. These uses are highly conditional and their efficacy is determined by the enemies you are standing against. Therefore PvP use is not recommended to the point of condonement. It should be noted that anyone using Vigorous Spirit, Mending, or Live Vicariously in PvP should not be surprised when their team deserts them.

Warrior/Necromancer

 * The most common usage of the Necromancer secondary is for condition removal via Plague Touch.
 * Blood is Power can be used for energy management for the group.
 * Rend Enchantments can be used as an enchantment removal.

Warrior/Assassin

 * The Assassin has a wide range of snares and shadow steps that can serve a Warrior well. Shadow Prison is an outstanding skill in this vein.
 * Signet of Malice can provide free condition removal.
 * Dash is an excellent speed boost that also serves as a quickly recharging cancel stance for Frenzy.
 * Death's Charge is useful for closing distance in battle, but take care not to outrun your party's support.
 * Iron Palm can be an alternative to Shock.
 * Disrupting Dagger is a useful interrupt that cannot be blocked or miss.

Warrior/Ritualist

 * Spare use of Weapon skills can benefit a Warrior; Splinter Weapon can be combined with Triple Chop or Hundred Blades. Ritualist primaries, however, far outclass Warriors at spamming weapon spells.

Warrior/Paragon

 * Remedy Signet may be used with no attribute points for a quick, energy-free method of condition removal.
 * Though a Warrior's shouts may effectively augment that of the Paragon's lack of the Paragon's primary attribute line will result in energy depletion.

Warrior/Dervish

 * Many Scythe Mastery skills are general-purpose Melee Attacks (i.e. Rending Sweep) rather than weapon-specific skills, which allows them to be used with axes, hammers, and swords.
 * A scythe can work in a Steady Stance/Drunken Blow/Desperation Blow build.
 * Rending Touch can be used as an enchant removal.
 * Pious Haste can be used as a speed buff and cancel stance.
 * Though more effective on a Dervish/Warrior, using Wild Blow can still result in obscene damage and stance removal in conjuction with a scythe.