New Player’s guide - I’m currently re-working this because a bunch has changed since I wrote it and I think there are quite a few things I want to add/improve.
Bonus potions and entrance speed guide
There’s a few others but those are probably the ones you want right now.
To your original post here…
It’s better to expand your collection of legendaries rather than purposefully hatch duplicates to get bonus. This is true even for veterans. New monsters are simply more valuable. The way to bonus legendaries is to get “legendary potions” from limited-time events and PvP. These let you increase the bonus on specific legendaries you care about. Over time, you’ll get most of your important ones to +9.