Now I've got two friends who made actively horrible casual decks, and we're making more. Got a few other folks interested as well.
The ethos of this format is basically:
1. play almost entirely bad cards that rarely if ever see play otherwise
2. don't overload on synergy and velocity
3. have an aesthetic in mind for your deck
I have two trash decks - mindless tribal fungus that attacks the last person who attacked it, and does not communicate about the board state, and my orzhov midrange with such beauties as Ashes to Ashes, General Jarkeld and Hypnotic Specter.
One friend built Fumiko the Lowblood tribal samurai and eastern themed equipment/effects, and another built some kind of weird green stompy deck with +1/+1 counters that was a bit overgood.
We've been playing against other people's lower power decks thus far, and overall creating pretty interesting games that don't require as much hyperanalysis and attention to board states and so on. There's still some amount of play skill involved, but there's a lot of deck slot machine randomness.
I wouldn't pretend that I could play this way all the time but it definitely shakes things up and pushes people's thinking to finding cards that they wouldn't normally play, and to look at reasons to include cards other than power level.
Things I've generally (lol) found about how to build a bad deck that takes a long time to do things but doesn't get run over --
1. Play a bad commander. If your commander is strong, every trashmander game will revolve around that strongly. Having a commander that does *something* but not too much is difficult and probably the single most limiting factor for trashmander. Almost every new legendary creature is overwhelming, single handedly influencing games and making vanilla creatures meaningless or generating tons of card adantage.
If you avoid commanders who generate card advantage or steamrolling advantage, it helps a lot at keeping things tame.
2. Play some removal but avoid overloading on sweepers.
3. Incremental rather than explosive card advantage. In my Selenia, Dark Angel deck I have CA engines like Disturbed Burial, Necrologia and Jayemdae Tome.
4. Combat is important in slower games, so things that influence combat are often good points to interact at. Reverse Damage has been pretty good for example.
Similarly be careful about recurring lifegain - a big lifelinker can just shut off any racing pretty fast. Cards like Sunscorch Regent or Soul Warden can be of outsized effect.
I found Icy Manipulator and Royal Assassin to both be borderline too strong when people're trying to incrementally win with combat
5. Just don't search your library so damn much.
