The only time I made a chapter, I called them the Storm Tigers (garish orange paint scheme, 5th company (black trim and kneepads), green eyes, etc).
Steel Blades (they hate the Iron Warriors, and steel is better than iron?)
Erm
Astral Blades?
Astral Spears?
Night Slayers?
Fire Hunters?
Brotherhood of Steel?
Emperor's Spears (or Spears of the Emperor)?
Sword Brothers (I'm pretty sure that's been used actually...)
Iron Dragons?
Fire Dragons?
Avenging Swords?
Siege Brothers?
Wings of Fire (or Fire Wings)?
Steel Hammers?
Adamantium Avengers (erm, what?)?
Steel Foxes?
Star Spears?
I'm painting a group of marines for my local gaming group (I've decided I'll give them to our local Golden Demon winner - maybe he'll make them look better after I've finished with them), and they'll be called either the Solar Spartans, or the Stellar Spartans - colour scheme of black, with red trim, and gold helms, to go with the club symbol of the Surrey Spartans.
Dorn's Hammers (successor chapter maybe?)
Guilliman's Avengers (I guess they must hate the Emperor's Children then)
Steel Templars
Fire Zealots
Star Fangs?
There's a generator here that would probably do a better (or at least the same) job than me.
https://www.battle-brothers.co.uk/space-marine-chapter-name-generator/And sorry for not mentioning it earlier, but the improvements you've made to the mini do look great.