Secondary professions for a Warrior

Warrior/Ranger

 * The Ranger line offers a few alternative IAS skills.

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.
 * Hex Breaker is otfen 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.
 * Though expensive, Healing Breeze can, when paired with a defensive stance and high armor, provide a safe self heal, however, the same investment in Tactics for Healing Signet can provide more health, at the cost of some defense. On the other hand, Restful Breeze can provide a cheap heal and relatively low levels of Healing Prayers. Though it cannot be used whilst attacking, it can be useful in some situation, such as in a retreat. Despite its drawbacks, it could be better than Healing Signet in that it is less prone to interrupts, does not decrease armor, can be used on other players, and heals for more under the same attribute level, especially if switched to an enchanting mod.

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 battel, 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.
 * Consume Soul can be used to counter Spirit spamming, as a warrior is fairly dangerous even without an elite skill.
 * Death Pact Signet can be used in a situation where you can control deaths effectively (such as in PvE). Alternatively, Flesh of my Flesh could be used as a hard rez.

Warrior/Paragon

 * Remedy Signet may be used with no attribute points for a quick, energy-free method of condition removal.

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.
 * The Warrior can make use of the Dervish's cheap Enchantments to add damage types and other effects to attacks.
 * A scythe can work in a Steady Stance/Drunken Blow/Desperation Blow build.
 * Rending Touch can be used as an enchant removal.