as a flash host,

means flash
dice

its when they use dice during the hunt (an object u got during previous hunts) and it gives u more cash and drops (its usually in ca how much more % ur finally drops will get to)
and jet

is something like dice but more expensive to find for the hosts and also buy since it's expensive. and I believe it only gives 20% drop boost (but I'm not 100% sure since I barely join flashes with jet)
and the

I literally have no idea so maybe ask the person that u saw it from? maybe u saw it for a byoc banner which is like paying ihs like an ecs club