One very simple anti-great-filter theory is that we're simply the first. Someone has to be by definition, it's a small chance but it definitely is a possibility.
Depending on how the universe works we only need to be the first in the galaxy (the chance for which is not that low). Also we can just be in the galactic backwater. there are places on earth we know nothing about. So the idea that we are in a part of the galaxy equivalent of the deep amazonian jungle is also not far fetched.
And the galaxy may be brimming with life - just so alien that we cannot recognize each other.
"Far out in the uncharted backwaters of the unfashionable end of the western spiral arm of the Galaxy lies a small unregarded yellow sun. Orbiting this at a distance of roughly ninety-two million miles is an utterly insignificant little blue green planet whose ape-descended life forms are so amazingly primitive that they still think Apple watches are a pretty neat idea."
I'm partial to the Great Filter being behind us as the evolution of sentience combined with tool use. There has been ample time and opportunity for 'us' to evolve on this planet, yet it took until now. The Dinosaurs were around for nearly 200 million years and got nowhere, and if that rock hadn't hit the Earth 65my ago, we wouldn't be here, and there are many other events which could also have put an end to our line. So my guess is human level intelligence is very, VERY rare, which would be very sad and I hope its not the case.
I always think of dogs, dolphins, and whales when people mention this. Elephants fit in there too. Is there sentience, but just not tool use in our backyard?
