I don't have too many gems so I want to spend them wisely. I know Vermillion Dragon Mech is the best 9*, Scrap Dragon's the best 8* and Black Rose Dragon's the best 7*, but what are the best basic-material synchros for all other levels?
I'm not logged in right now so can't say the actual named, but:
Best level 6 is the dolphin that reduces an opponents monsters attack in half each turn and can be SS from the graveyard.
Best level 7 is probably the samurai then Black Rose Dragon
An alternative level 8 is red dragon archfiend that is also the best signer dragon for raid boss events.
for 12 star is obelisk the tormentor
For 5*, it's Armades Keeper of Boundaries.
For 6*, it's Brionac Dragon of the Ice Barrier.