Dagger, Dagger, Dagger goes very nicely with both Vax and Vex
Thats a bit narrow, but as time passes we get more and more options for colored artifact creatures and Arcbound Ravager and friends show up in more and more Cubes
If youre sitting there saying I want card A because it works well with card B but it doesnt work well with anything else and doesnt contribute to some grand strategy, it should probably get cut
Probably not, but there is always a chance
Haunted Dead springs to mind for a creature you wouldnt mind drawing four cards from
Early sets included a few cards with rules designed to interact with this gambling aspect, allowing replacements of cards up for ante, adding more cards to the ante, or even permanently trading ownership of cards in play