For me, these are also biased especially for some devs or teams behind retroactive airdrops, because they are the ones who will know it first, they are the ones for sure will take action first to qualify in airdrop for sure, and there will be still a lot of manipulations.
Could be true for individual team members but otherwise projects usually allocate team supply from distribution.
IMO, retrospective airdrop has been successful only because there is only positive in creating and distributing tokens. It brings hype, and projects get lot of treasury, and community get free money. It's win-win situation for parties involved.
Couple more potential ones:
1) DOP testnet:
https://doptest.dop.org/Incentivized testnet, should take 10-20 minutes to complete tasks.
2) Redbellynetwork:
https://RBNT.zealy.ioZealy quests are useless most of times but this Twitter response [1] from RBNT team made me do it.
[1]
https://twitter.com/RedbellyNetwork/status/1704364030280999071