There is no best Ichorid deck. There is just waaaaay to much graveyard hate out there.
Leyline of the Void turn 0!!!
Pithing Needle your Bazaar of Baghdad.
Extirpate your Bridge from Below.
Tormod's Crypt your entire Yard.
Yixlid Jailer turns off Dredge effects, and removes flashback and all abilities of cards in any graveyard. Welders still work though!!!
I'm an ichorid player myself so I can deal with most of the stuff people sb against it. The only viable deck I see ichorid having a problem against is Stax and Flash. But all ichorid deck should main Cabal Therapy, Leyline of the Void and Chalice of the Void. Leyline helps against Flash and stax. Unless the person is smart enough to run
Chain of Vapors but you are right about there's no perfect Ichorid deck. I main Dryad Arbor, Serum Powder. I've only seen 2 versions of Ichorid. One Abusing Serum Powder for a bazaar for the abuse of using Dragon's Breath and Sultured Ghoul with Dredge Return. The other one using Flame-Kin Zealot.
Leyline of the Void is easy to take care of with
Reverent Silence Simplify Ray of RevelationPithing Needle Oxidize will take care of this.
Extirpate I'm not going to argue with you on this one. Who's going to SB 4 Extirpates against Ichorid? IMHO(In my honest opinion) it's a waste of space in your sb. You'll have to Extirpate the main spells in the graveyard which is
Dredge Return and
Bridge from Below I think...
Echoing Truth a better SB against Ichorid. I mean who cares they have X amount of tokens.
Tormod's Crypt I smell
Chalice of the Void for 0
Yixlid Jailer is just a measely 2/1 that can be taken care of with
Contagion