The last time I remember with good welcome bonus is Winz.io because they don’t have wagering requirements on their bonuses. You just need to wager your deposit x1 and you are good to go.

Their welcome bonus is in the form of free spin so the amount of your bonus depends on your luck when spinning slot games.

You can also try Betpanda since it offers a weekly cashback plus game of the week cashback which is awesome if you have a bad luck on slot games.