Secondary professions for a Necromancer

Necromancer Warrior

 * This profession combination provides little benefit for a Necromancer primary.
 * Since the Necromancer is rarely a party support role, the Tactics line is less useful then would be expected.
 * Meleemancers, or necromancers using melee weapons, are rarely effective, and often snubbed by experienced groups.

Necromancer Ranger

 * Serpent's Quickness can accelerate slow recharging spells.
 * Energizing Wind can cut down the cost of 25-energy skills such as Animate Bone Fiend to manageable levels.

Necromancer Elementalist

 * Glyph of Lesser Energy can be used for energy management.
 * although popular, a Necromancer using Fire Magic is rarely effective, and often disparaged by more experienced players.

Necromancer Mesmer

 * Skills in the Inspiration line such as Ether Signet and Leech Signet can be used for additional energy management.
 * Mantra of Inscriptions combines with Signet of Lost Souls for energy management.
 * Echo and Arcane Echo can be used to increase the damage potential of some of the longer recharging necromancer skills.

Necromancer Monk

 * the 55hp solo Necromancer is a very effective farming tactic.
 * Since the Necromancer is rarely a party support role, Utility skills from the monk lines are not terribly effective.
 * Minion Masters using Healing Prayers are rarely as effective as minion maintenance with Blood of The Master.

Necromancer Assassin

 * Deadly Arts hexes such as Enduring Toxin can be combined with a Necromancer's hexes.
 * Signet of Toxic Shock and other deadly arts combines well with Toxic Chill.
 * Enduring Toxin, Mark of Death and other deadly arts hexes combine well with Soul Barbs.

Necromancer Ritualist

 * A Necromancer spirit spammer rarely has to worry about running out of energy.
 * A Necromancer can function as a healer using Restoration Magic, managing it's energy with the Soul Reaping bonus.

Necromancer Paragon

 * A minion-master can use "Fall Back!" to heal his army on the move, however, this is one of the very few shouts that affect minions.

Necromancer Dervish

 * Mystic Regeneration can combine with necromancer enchantments such as Dark Bond and Aura of the Lich, but this tactic is easily outpaced by Blood Renewal.