Secondary professions for a Ranger

Ranger/Warrior

 * Energy-based melee attacks are affected by Expertise, thus allowing a Ranger to use them at reduced cost.
 * Rampage as One provides quick adrenaline gain when combined with skills from the line of Hammer Mastery. These rangers are often referred to as "Bunny-Thumpers," because of the way they run when carrying a hammer.

Ranger/Monk

 * Mending Touch is useful for condition removal, however Antidote Signet can in some situations be better than it.
 * Rangers have efficient self heals and should not invest in Healing Prayers.
 * Resurrection skills such as Rebirth are useful on primary rangers, because rangers tend to have better survivability than other professions and can save a party from a near Party-wipe.

Ranger/Necromancer

 * The "Touch Ranger" takes advantage of Expertise's effect on touch-range skills. This, combined with ranger defensive stances and speed boosts, makes a powerful build with decent armor ignoring damage and potent healing.

Ranger/Mesmer

 * Echo chains can be useful when trapping.

Ranger/Elementalist

 * Elementalist spells such as Conjure Flame can be combined with Barrage to deal extra damage.
 * Kindle Arrows can be coupled with Conjure Flame to deal a substantial amount of damage without the necessity of a fiery bowstring.

Ranger/Assassin

 * Rangers get very little benefit from this profession combination.

Ranger/Ritualist

 * Weapon Spells such as Splinter Weapon, Nightmare Weapon and Brutal Weapon can work well with a bow. They combine with Barrage and Dual Shot to create a potent damage spike.
 * Reusable Ritualist resurrection skills such as Death Pact Signet or Flesh of My Flesh can be useful.

Ranger/Paragon

 * Energy-based spear attacks are affected by Expertise, thus allowing a Ranger to use them at reduced cost.
 * Song of Concentration can be used to set traps in the middle of battle.

Ranger/Dervish

 * Expertise can be used to reduce the energy cost of scythe attacks. Combined with Ranger stances such as Escape or Lightning Reflexes, this makes a fast running or fast hitting, hard to damage and multi-hitting Ranger.