There are many useful links and tools generated by the wonderful E7 community.
I would like to share a few tools that I find very very helpful.
This simulator lets you enter your team and tells you the options to generate the most happiness. This is very important if you would like to progress in Labyrinth
Optimize your hell raid route! For late game players
This shows where are the best places to farm certain catalysts
This shows the minimum and maximum amount of substats you gain when you upgrade your gear.
Also, highly recommend joining Epic Seven Discord channel. There is tons of more guides and friendly people that are willing to help.
Epic Seven made easy~ Until next time!
Shows which heroes benefit from Flat Stat more than % Stat.