https://tappedout.net/mtg-decks/cheapskate-derevi-competitive-100-budget/
Infinite Damage:

Our infinite damage combos revolve around repeatedly sacrificing Derevi to Blasting Station .

Derevi, Empyrial Tactician + Dawn's Reflection / Market Festival + any land that taps for two or more mana ( Simic Growth Chamber , Selesnya Sanctuary , Azorius Chancery , or Lotus Field ) + Blasting Station = infinite damage.

Derevi, Empyrial Tactician + Naban, Dean of Iteration + any combination of bounce duals ( Simic Growth Chamber , Selesnya Sanctuary , Azorius Chancery ) or any land enchanted with either Dawn's Reflection or Market Festival + Blasting Station = infinite damage. Derevi, Empyrial Tactician + Naban, Dean of Iteration + Faeburrow Elder + Blasting Station = infinite damage.

Derevi, Empyrial Tactician + Krosan Restorer (with threshold) + any combination of bounce duals ( Simic Growth Chamber , Selesnya Sanctuary , Azorius Chancery ), or any combination of three lands producing + Blasting Station = infinite damage.

Tutor for combo pieces with Wargate , Eladamri's Call , Congregation at Dawn , Yisan, the Wanderer Bard , Momir Vig, Simic Visionary , Heliod's Pilgrim , Totem-Guide Hartebeest , and Muddle the Mixture .
Infinite Mill:

Our infinite mill combos revolve around repeatedly sacrificing Derevi to Altar of Dementia .

Derevi, Empyrial Tactician + Dawn's Reflection / Market Festival + any land that taps for two or more mana ( Simic Growth Chamber , Selesnya Sanctuary , Azorius Chancery , or Lotus Field ) + Altar of Dementia = infinite mill.

Derevi, Empyrial Tactician + Naban, Dean of Iteration + any combination of bounce duals ( Simic Growth Chamber , Selesnya Sanctuary , Azorius Chancery ) or any land enchanted with either Dawn's Reflection or Market Festival + Altar of Dementia = infinite mill.

Derevi, Empyrial Tactician + Naban, Dean of Iteration + Faeburrow Elder + Altar of Dementia = infinite mill.

Derevi, Empyrial Tactician + Krosan Restorer (with threshold) + any combination of bounce duals ( Simic Growth Chamber , Selesnya Sanctuary , Azorius Chancery ), or any combination of three lands producing + Altar of Dementia = infinite mill. Tutor for combo pieces with Wargate , Eladamri's Call , Congregation at Dawn , Yisan, the Wanderer Bard , Momir Vig, Simic Visionary , Heliod's Pilgrim , Totem-Guide Hartebeest , and Muddle the Mixture .
Counterspell Lock:

Our counterspell lock combos revolve around repeatedly sacrificing Derevi to Voidmage Prodigy . It is not a hard lock (but it is close).

Derevi, Empyrial Tactician + Naban, Dean of Iteration + Voidmage Prodigy + any two lands that tap for four or more colored mana (any combination of Selesnya Sanctuary , Azorius Chancery , Simic Growth Chamber , or Lotus Field enchanted with either Dawn's Reflection or Market Festival ) = infinite counterspell.

Derevi, Empyrial Tactician + Naban, Dean of Iteration + Voidmage Prodigy + Kiora's Follower + a land that taps for four or more colored mana Selesnya Sanctuary , Azorius Chancery , Simic Growth Chamber , or Lotus Field enchanted with either Dawn's Reflection or Market Festival ) = infinite counterspell.

Derevi, Empyrial Tactician + Krosan Restorer (with threshold) + Voidmage Prodigy + any three lands that in combination tap for = infinite counterspell.

Tutor for combo pieces with Wargate , Eladamri's Call , Congregation at Dawn , Yisan, the Wanderer Bard , Momir Vig, Simic Visionary , Heliod's Pilgrim , Totem-Guide Hartebeest , and Muddle the Mixture .
Stasis Lock:

Our Stasis locks revolve around giving our creatures vigilance and evasion to generate tap/untap triggers via Derevi’s triggered ability. These are not a hard locks, but they are oppressive.

Stasis + Brave the Sands or Serra's Blessing + Derevi, Empyrial Tactician = indefinite stasis.

Use Muddle the Mixture to tutor for combo pieces.

Stasis + Forsaken City + ample card draw = near-indefinite stasis

Use indefinite stasis in conjunction with Thalia, Heretic Cathar / Archon of Emeria + Archetype of Imagination or Wonder for a harder lock.

Use in conjunction with Thalia, Heretic Cathar / Archon of Emeria + Tetsuko Umezawa, Fugitive for a harder lock.

Copperhorn Scout is also a limited combo enabler.

The Stasis lock requires us to deal combat damage in order untap a blue mana source to pay Stasis’s upkeep cost, be be cognizant of that.

Tutor for combo pieces with Wargate , Congregation at Dawn , Yisan, the Wanderer Bard , Momir Vig, Simic Visionary and Muddle the Mixture .
Stax:

Our stax pieces are largely hatebears that tax non-creature spells, with a few exceptions.

Vryn Wingmare , and Glowrider each tax non-creature spells each (or total). Our deck consists of mostly creatures in order to break parity.

Squeeze taxes all sorceries (such as board wipes) . We run only one sorcery.

God-Pharaoh's Statue generally taxes all opponents spells .

Unsettled Mariner taxes opponents to target our permanents.

Dovin, Hand of Control taxes opponents instants, sorceries, and artifact spells by .

The total taxation is as follows: our creatures , opponents’ creatures , our non-creature spells (excluding sorceries) , opponents’ non-creature enchantment spells , opponents non-creature artifact spells , opponents instants , our sorcery spell , opponents’ sorceries .

Plus, add to the cost of all spells and abilities that target our permanents.
Hate:

Aven Mindcensor asymmetrically shuts down tutors.

Kataki, War's Wage symmetrically taxes artifacts out of existence.

Deafening Silence symmetrically reduces non-creature spells to one per turn. We have few.

Drannith Magistrate asymmetrically shuts down opponents casting cards from exile or the command zone.

Lavinia, Azorius Renegade asymmetrically shuts down opponents who cast spells for free or rely on non-land mana.

Gaddock Teeg symmetrically shuts down non-creature spells with CMC 4+ or with in the casting cost. This protects us from many wipes and wins (but notably not from Cyclonic Rift , which remains a threat; and it also hampers a few of our our own spells, notably Wargate and our land enchantments).

Archon of Valor's Reach symmetrically shuts down whatever we need it to (likely instants or sorceries).

Stoic Angel symmetrically shut down all but one creature untap per untap step. It’s vigilance breaks parity.
Card Draw:

Oakhame Adversary , Ohran Viper , Edric, Spymaster of Trest Toski, Bearer of Secrets , and Deepfathom Skulker provide card draw when our evasive creatures deal combat damage.

Skyward Eye Prophets and Arcanis the Omnipotent can be abused with Derevi’s untap triggers.

Momir Vig, Simic Visionary can produce consistent card advantage as well.
Mana Acceleration:

Sol Ring is our only mana rock.

Llanowar Elves , Fyndhorn Elves , Elvish Mystic , Boreal Druid , and Avacyn's Pilgrim , and Maraleaf Pixie are our basic mana dorks.

Faeburrow Elder , Krosan Restorer , and Kiora's Follower are our most important mana dorks as they enable our combos.

I would be remiss not to mention that stacking untap triggers to abuse Skyward Eye Prophets can yield incredible land acceleration.