when you say "iconic" are you talking about only the most successful spellbooks or all tournament-viable ones?
When I thought about what spellbooks to nominate, I was thinking along the terms of ones that have had the most impact on the meta, whether that be by winning tournaments or implementing new strategies that had not been used before that ended up being successful on a regular basis. Just my two cents.
I suppose the most successful books will always be the most "iconic" books if we go by that reasoning. And that's not necessarily a bad thing. There's already a thread of every (more like almost every) spellbook that has been posted
-->HERE<-- so we don't need another one doing the same kind of thing. Granted, that list hasn't been updated since April but still.