Activate Skirge Familiar by discarding Golgari Brownscale, adding {B}.
Activate Greed by paying {B} and 2 life, causing you to mill two cards and return Golgari Brownscale from your graveyard to your hand.
Golgari Brownscale triggers, causing you to gain 2 life.
Repeat.

Infinite self-mill

Near-infinite lifegain triggers

Near-infinite self-discard triggers

Golgari Brownscale

Greed

Skirge Familiar

Activate Golgari Brownscale's cycling ability by paying {0} and discarding it, causing you to mill a number of cards and return Golgari Brownscale from your graveyard to your hand due to its dredge ability.
Repeat.

Rhet-Tomb Mystic

New Perspectives

Attempt to draw a card. 
The draw will be replaced by Chains of Mephistopheles, instead causing you to discard Golgari Brownscale. Then, the draw will be replaced by Golgari Brownscale's dredge ability, causing you to mill cards and return Golgari Brownscale from your graveyard to your hand.
Dredger's Insight's first ability triggers, causing you to gain 1 life.
Lich's Mastery triggers, attempting to draw a card.
Repeat from step 2.

Near-infinite lifegain

Chains of Mephistopheles

Dredger's Insight

Lich's Mastery

Put a +1/+1 counter on Benthic Biomancer.
Benthic Biomancer triggers, causing you to mill two cards and return Golgari Brownscale from your graveyard to your hand, and then causing you to discard Golgari Brownscale.
Thran Vigil triggers, putting a +1/+1 counter on Benthic Biomancer.
Repeat from step 2.

Thran Vigil

Benthic Biomancer

Activate a permanent by tapping it, adding at least {B}.
Activate Mind Over Matter by discarding Golgari Brownscale, untapping the mana-producing permanent.
Activate Greed by paying {B} and 2 life, causing you to mill two cards and return Golgari Brownscale from your graveyard to your hand.
Golgari Brownscale triggers, causing you to gain 2 life.
Repeat.

Combos with "Golgari Brownscale"