As the title suggests, this is a fairly basic proposal and an idea that has been thrown around before. However, this could easily tie into marketing and engagement so it's worth re-evaluating. There is a fair amount suggested below, so I appreciate if it's TLDR. But I think it could help with engagement.
-- Sappy Seals have just swept 42 seals from the floor. This is just over 20eth for promotions/marketing etc.
I propose doing similar. A 10-15ETH sweep of Vamps, and a 5ETH sweep of Vampiresses. 15ETH of Vamps would currently provide 64 vampires to the treasury. 5ETH of Vampiresses would be 126 Vampiresses to the treasury.
I would propose running a Twitter marketing campaign to join the Discord and play games to win Vamps/Vampiresses.
There are Discord bots that can be used to tally points earned by playing in-discord games like quizzes etc and the winner each day, or each week, could win certain prizes. Eg, top 3 for a week all get Vamps. Top 10 get Vampiresses. You could have Discord roles based on your region for which competition zone you want to join, to allow 'fair chance' for all regions.
There are also Discord bots for RPG like elements/dungeons which could be used (see Avarik Saga). The dungeons open at a certain time and people type bot commands to 'attack' the monster. There is a cool-down to avoid spamming. Power is determined by your Discord rank from chatting, so it encourages people to hang out and chat so they are stronger in dungeon fights. This could work well with the meta idea of Vamps, eg, Vamps fighting against Vamp Hunters in the dungeon etc.
You could also run special events on weekends with Smash Karts competitions with first place winning a Vamp and 2nd/3rd winning a Vampiress. Equally you could do the same with TetrIO battles or other community games.
All of this could be spread out over the course of 12-16 weeks, possibly longer. It would help newcomers to the NFT community be engaged because they could possibly get a 'free' NFT by joining an established project and interacting with the community. It would also bring other communities into ours with the chance of winning prizes.
If someone were to win a Vamp and Vampiress, they would only need to buy a Bat on secondary to have a family for blood boosts. So it might incentivize the purchase of Bats too.
I understand the argument would be "They will just sell", but newcomers might be more likely to hold if they've enjoyed being welcomed to the community, had fun with other vamps playing games and feel included. It would make current holders more engaged too, and feel like they stand a chance at being rewarded. There could be Vampiress only competitions for those only holding Vampiresses to 'upgrade' to earning/winning a full vamp. This would reward Vampiress holders who have been looking for more utility.
The prizes could also be distributed sparingly to avoid flooding the floor. As mentioned, there could be special events on weekends, and a points table that tallies over the week. This could potentially limit the numbers being won to 5-10 Vamps a week and 20 vampiresses.