So I don't have all the pieces in which to make MonoWTeshar, Ancestor's Apostle as fast as it can be, so what I have been doing since Dominaria instead has been adding a color or two and sneaking a Teshar oriented artifact strategy into the deck in essence have been cutting the deck with a large influence of another colors strengths.
The fact that she gives tokens Vigilance and Lifelink is graaaavy ontop of her first ability which takes everything this deck wants to do and kicks it into overdrive.
Alongside Teysa's ability adding in B also pulls in the best tutors in the format to smooth our way to Teshar and friends the myriad other ways that Black impacts what this deck can become I think turns it into a really potent beast.
I like his deck a lot. This version of Teysa is by far my favorite. Seems like it has the most potential for fun to me. And your deck list supports that.
This is probably a dumb question, but have you considered testing Heartless Summoning? It may do more harm than good.
I largely moved away from playing her and this deck but I imagine Heartless would work well even through all the times when it would interfere with something.
It worked okay as GW with Saffi Eriksdotter
Worked really well as UW with Raff Capashen, Ship's Mage
Then I took a break but then Teysa got spoiled
The fact that she gives tokens Vigilance and Lifelink is graaaavy ontop of her first ability which takes everything this deck wants to do and kicks it into overdrive.
As Such:
1 Teysa Karlov
Creature
1 Blood Artist
1 Recruiter of the Guard
1 Stoneforge Mystic
1 Pitiless Plunderer
1 Priest of Gix
1 Mentor of the Meek
1 Gonti, Lord of Luxury
1 Teshar, Ancestor's Apostle
1 Xiahou Dun, the One-Eyed
1 Sidisi, Undead Vizier
1 Mikaeus, the Unhallowed
1 Grave Titan
1 Razaketh, the Foulblooded
Enchantment
1 Land Tax
1 Necropotence
1 Carnival of Souls
Land
1 Strip Mine
1 City of Brass
5 Swamp
1 Volrath's Stronghold
6 Plains
1 Cabal Coffers
1 Arid Mesa
1 Command Tower
1 Cavern of Souls
1 Reliquary Tower
1 Godless Shrine
1 Mana Confluence
1 Urborg, Tomb of Yawgmoth
1 Bloodstained Mire
1 Flooded Strand
1 Polluted Delta
1 Windswept Heath
1 Inventors' Fair
1 Marsh Flats
1 Fetid Heath
1 Phyrexian Tower
1 Mana Vault
1 Urza's Bauble
1 Ashnod's Altar
1 Lotus Petal
1 Scroll Rack
1 Claws of Gix
1 Voltaic Key
1 Phyrexian Altar
1 Chromatic Sphere
1 Welding Jar
1 Grinding Station
1 Krark-Clan Ironworks
1 Sensei's Divining Top
1 Chromatic Star
1 Expedition Map
1 Nim Deathmantle
1 Myr Turbine
1 Orzhov Signet
1 Skullclamp
1 Chromatic Lantern
1 Gilded Lotus
1 Sol Ring
1 Chrome Mox
1 Aetherflux Reservoir
1 Treasure Map
1 Hangarback Walker
1 Walking Ballista
1 Junk Diver
1 Myr Retriever
1 Workshop Assistant
1 Dross Scorpion
1 Foundry Inspector
1 Scrap Trawler
1 Corpse Dance
1 Culling the Weak
1 Enlightened Tutor
1 Cabal Ritual
1 Goryo's Vengeance
1 Path to Exile
1 Anguished Unmaking
1 Vampiric Tutor
1 Entomb
1 Teferi's Protection
Sorcery
1 Demonic Tutor
1 Yawgmoth's Will
1 Reanimate
1 Tendrils of Agony
1 Living Death
1 Merciless Eviction
1 Toxic Deluge
1 Dark Petition
1 Night's Whisper
Planeswalker
1 Kaya, Ghost Assassin
Alongside Teysa's ability adding in B also pulls in the best tutors in the format to smooth our way to Teshar and friends the myriad other ways that Black impacts what this deck can become I think turns it into a really potent beast.
This is probably a dumb question, but have you considered testing Heartless Summoning? It may do more harm than good.