I usually use Shooting Gallery with Equinox, but mixing Gloom with Maim should have some very interesting results:

Synergies:

• Gloom + Maim = Lifesteal on enemies within Gloom's range taking damage ticks from Maim.
• Gloom + Maim = The stun from Maim will be really really slow. Enemies will be frozen for quite a while.
• Gloom + [Rage] = Enemies hit by Rage within Gloom will be sped up by 31%, but slowed by 54%, for a net slow of 23% WITH a damage vulnerability of 71%!
• Gloom + Rage = Enemies hit by Rage far away (up to 95m) will haste-hurry to get to you, then be slowed down when within 30m.
• Gloom + Rest = Using rest for some reason will result in dramatically slower animations of going to sleep and waking up.
• Gloom + Mend = Teammates within 30m of you will be having their shields replenished by you, and will also have lifesteal for themselves.