There were a few other marketplaces that started when FlashDen started. I just searched my email archive and found Collis (Envato's then-CEO) asking me for an interview for FlashDen (late 2006).
I'm a happy customer of Envato and now I'm happy for them.
Edits:
1. Here is their story https://www.envato.com/blog/the-story-of-envato/
2. I contributed to one of their competitor (a friend from the community) for equity in the company (something like that) but the company went bust after his divorce. One thing I remember with that story was of McCoy’s dialogue to Kirk in Star Trek,“I got nowhere else to go. The ex-wife took the whole damn planet in the divorce.”