I would go for the most easy way, head over to AirdropAlert.com

Can submit your airdrop easily here: https://airdropalert.com/airdropsubmit

Or read more on marketing & promotion of airdrops before you list your crypto airdrop campaign: https://blogs.airdropalert.com/airdrop-promotion-start/

Other sites to look at are:
Airdropster.com
BountiesAlert.com
Earn.com
Tokendrops.com
Airdropland.com
CryptoAirdrops.io
Airdropter.com
AirdropExpert.com
CryptoFrenchies.com