i think there should be some more bossters so i have listed some below
1.event heroic sense
event booster like heroic sense for event items which spots the event items because it takes a lot of time to find event items and we have to go through every zone and find them so that will be really helpful
2. booster for coins and exp
a booster that boosts the coin and exp rate of missions simply as it's alredy in the game 10% a 25% and 50% cost can be same
3.weak one spotter booster
a booster that will spot any weak hero with lots of honor so u can defeat and win lots of honor and that could help in loosing honor to for unequipped heroes who are trying to do good in next weekly tournament.
and well it's not a booster but when you win in duels you can get or can rob some coins from the opponent coins rewarded in duels are very low so if someone have 1000000 so you can rob 0.5 % of the the amount if you win it means 1000 coins that's it