I like your deck concept, and I would like to make a few suggestions as someone else who built a Teysa, Envoy of Ghosts commander deck. Because of the large number of creatures you are likely to get, you want synergy with those creatures. So, here are my suggestions, keeping in mind the tokens are 1/1 Flying black and white spirits:

First, Pontiff of Blight . He gives all your creatures extort, so you should always have a useful mana dump when you are able to play a spell.

Second, Paragon of New Dawns and Paragon of Open Graves . While their secondary ability isn't super useful in this deck, giving all your creatures a passive buff is.

Honor of the Pure and Bad Moon , for similar reasons, but unfortunately Bad Moon can buff opponents' decks, too.

Exquisite Blood , so opponents' life loss will give you more life, and you already have Sanguine Bond .

True Conviction , for that double strike and lifelink on everything.

Vault of the Archangel , for alternative lifelink and deathtouch on everything.

Necropotence or, if you don't like skipping your draw phase, Erebos, God of the Dead for card advantage.

My last two suggestions for now are a bit more pricey, but if you are willing to spend the money, then Liliana Vess and Sorin, Lord of Innistrad , Liliana for deck stacking and Sorin for emblems.

Penthoplayer, thank you for commenting. I playtested with Pontiff of Blight , and both paragons, they did not make the cut, I do like the rest of your suggestions and I will try to work them in if I can.

Thanks. If you want to see mine, it's the unimaginatively titled Black/White Lifelink/Extort. Although, I think I already gave you all the good synergy cards in it, and even some I want but don't have.

My friend Nautas is playing a Phenax EDH, it is sooooo annoying. Luckily I have a Bruna, Light of Alabaster aura deck to say "Ha Hah". But, thank you for the comments/suggestions.

Oh, and Serra Ascendant is strong in any EDH deck, wnd Concerted Effort gives mass bonuses. Might also want a Seraph of the Masses for it's crazy strong power and toughness. Lastly, for now, Mistmeadow Skulk stops most opponents' creatures as a blocker.

Oh, and you need to replace Sandsteppe Citadel , can't be able to produce green in this deck.

I forgot to update this, the citadel is now an Evolving Wilds, i didn't even consider a lot of these cards. now I need to order some more, lol.

Thank you for the suggestions!