I mean, you don't even have to look very far.
Gavin's faucet used to give out 5 BTC at a time.
Yes, this faucet was the biggest known.
Amount given per claim: 5 BTC
Daily distribution limit: Initially around 1,100 BTC/day
Around 19.000 BTC distributed.
BTC price at the time: Less than $0.01 to a few cents per BTC
Today’s value: Over $1.2 billion USD
Largest BTC payout per claim in history (5 BTC per person).
Other that I used at the time:
Freebitco.in (2013–present): Longest-running faucet, since some time there is a problem with withdrawals, wheel of fortune spins not credited anymore.
Moon Bitcoin, Cointiply, and BonusBitcoin popular back then as well but paid only fractions of a cent worth of BTC.
Gavin’s faucet helped seed thousands of early Bitcoin adopters. Like the Bitcoin pizza day, I see this very important for the adoption of bitcoin.