Not to sound flippant but....learn to convert models.
There have been plenty of games where characters, monsters, npcs and other things descriptions in books sounded great, but there isn't a mini for it. So I had to make them. With exactly knives, green stuff, kit bashing and other ways. And that was before hero forge and 3D printers were around.
I'm having to do this now for my upcoming champions game this summer. Either I use hero clicks or I roll up my sleeves and start making what I need.
Its not easy at times, I won't lie. But you aren't always going to find the miniatures you need. Its what I have learned over the years. Companies aren't going to have produced every conceivable miniature