Alright so Modern Horizon 3 just dropped some bi-colored modal lands!
Now they are not particularly great in this deck for actually what the spells are if casted, but rather they represent a way to get better percentages of hits from
Niv-Mizzet Reborn trigger, and represent lands that you can get from him.
Also the more cards you get in hand, the more cards you can discard to hand size setting up your graveyard for
Living End.
Waterlogged Teachings is good, there are a number of instants in the deck including a cascade in
Violent Outburst.
Rush of Inspiration is okay if you don't want to lose a card like a cascade for example, but the rest of the deck is truly fine with discarding at random, and even can help to fill graveyard with another fatty.
Drowner of Truth is another body, nothing fancy.
Bloodsoaked Insight got some potential, certainly would only cost
{b/r}{b/r} a lot of the time for a bit of extra value.
Strength of the Harvest and
Glasswing Grace as auras are not very exciting, but you can put them into play with
Hypergenesis giving a boost.
Suppression Ray realistically not going to cast it, but maybe if you are down to a single opponent this could be a finishing play.
Unfortunetely the Boris, Golgari, Gruul bi-colored modal lands are under 3 mana so don't work with the cascade.
I'm happy to play these over some of the tri-colored cycling lands. I'm fine doing this as the
Astral Slide part of the deck is the least frequent part of how this deck plays out and so having come into play tapped lands already, a straight swap doesn't change much. Color-fixing itself I don't have problems with either with all the land cycling fixing colors with already existing bi-colored lands.
Also tri-colored lands have really shot up in price over the years, and they have never really been that good costing a full
3 to cycle. So for anybody wanting to put the deck together this will help with budget.