Secondary professions for a Necromancer

Necromancer Warrior

 * This profession combination provides little benefit for a Necromancer primary.
 * Skills from the Tactics line such as "Shields Up!" can help the Necromancer and his teammates, but these bonuses are better offered by a warrior primary

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.

Necromancer Mesmer

 * Skills in the Inspiration line such as Power Drain can be used for energy management.
 * Mantra of Inscriptions combines with Signet of Lost Souls (and Leech Signet) 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

 * Spoil Victor is a powerful elite for a 55hp solo Necromancer.
 * A N/Mo could pack utility skills such as Draw Conditions and Convert Hexes to help out the party.
 * Minion Masters frequently employ Heal Area to maintain the ever-degenerating health of their minions.

Necromancer Assassin

 * Deadly Arts hexes such as Enduring Toxin can be combined with a Necromancer's degen hexes.
 * Signet of Toxic Shock and other deadly arts combines well with Toxic Chill etc al.
 * 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 to created a self-sufficiant minion-master.