In the original series, a prefix is really part of your cat's history or environment. 'Bramble-' suggests a thicket where they were born, 'Heather-' for the moors. That's the first layer. Then, the suffix is what they earned. A -'claw' could be a hunter, a -'pelt' just means they're good at camouflage, nothing flashy. I think people get caught up on making it sound cool and forget that in the clans, names are functional. My favorite from the books is probably 'Whitestorm'. It's simple—white pelt, but with the force of a storm in battle. It doesn't need to be overly complex to tell you exactly who he is.
I always lean towards suffixes like -'heart' or -'foot' for cats whose greatest strength is loyalty or endurance, not just fighting. 'Longtail' is a great example; his name literally describes him, and his skill was his keen sight and patience. It's not about being the fiercest, it's about what you contribute to the clan. I'd avoid made-up suffixes that aren't in the books, like -'blade' or -'fang'; it breaks the internal logic for me. Stick to what feels found in the forest.