Suggested lottery prizes:
City connect voucher – maximum one per era
A money jackpot – like the Gold rush, rare but completely fills your bank
A prestige reward comparable to era – for example 1000 prestige in Era 6
A worker contribution voucher – value 100k per era so Era 1 – 100k, Era 2 – 200k etc.
Increase the frequency of competitions so they are every 2 or 3 hours
Cheap Build Voucher as a prize
Instant Upgrade Vouchers
Maybe rare – city connect voucher
License voucher instead of license for goods
Instant Dispatch vouchers
Bonus Engine upgrade voucher
These are just my suggestions from experiences I've gained as a player, and things that I would love to see implemented in the game.