Vouch for hugeblack. Although the other suggestions aren't bad choices either.
OP, earlier, some members started a signature contest, where a prize was offered for the best signatures. It was a very good campaign, the brand was further promoted, and they received very high-quality proposals. The participants are also rewarded, so it can be said that it is a win-win situation.
Of course, the prizes should be good enough to attract the majority of signature designers to participate in such a campaign. Just a suggestion.