As steve said i would aim for Slaver and TPS/Long with the maindeck, and other then that i'd test against:
U/W Fish or some other fish variant - Always worth testing against if you ask me.
Workshop aggro or stax - Choose the one you think will be worst for you!

Ichorid - Well obv. Find out how much hate you need, or if it's better to just accept it as an auto-loss.
There's lots of decks you COULD test against, but most people don't have time to test against 20+ decks.
/Zeus