First and the main one is the affiliate/referal programas, this way by sharing your affiliate link you will get some incom from the users bets, isn't easy to get good affiliate (users who bet a lot) but with one high roller you could make a descent amount.
The second one is the VIP programas, like the one that stake offers, you need to bet to grow your account, but once you have a good VIP level you will get a weekly and monthly prizes, It will be better if you bet that month but even without betting you will get something each week/month.
Yeah, actually I think that's a good idea, but it will be very difficult for you to convince people to join using your referral link since your intention is just to get them to join the platform so you can get your offer, is only those who are addicted to gambling that can be easily convinced. Of course those who are addicted will always want to partner with all the whole betting platforms.
However, talking about vip program. actually I think I have come across such program before, but meeting up to the standard when you will get paid even when you don't gamble. is actually very difficult before one could get to that level, perhaps before you can even get to that level you must have lose a huge amount of money. and the amount you will lose in that process can not be compared with the amount they're going to pay you when you finally meet up to that level.