2 x 72 belts

(VSM Ceramic belts made in Germany) inexpensive but good
TruGrit has, $5 - $7 ea
https://trugrit.com/

Start with

Ceramic 36 grit for fast removal
piece will tend to stay cooler

60 grit ceramic - initial shaping
piece will warm

100 grit ceramic
piece will get hot

Finishing

3M Trizact
Will need belt cleaner
a bit pricey, but last a long time
from TruGrit, about $10 each

120 grit

220 grit

Polishing

Scotchbrite
But alternative brand (Red Label)
Also good for mill scale
Red Label Abrasives 2 X 72 Inch Non Woven Surface Conditioning Sanding Belts for Knife Makers and Metal Fabricators - Coarse, Medium, and Fine Grits - 3 Pack Assortment. Set of three about $50 from Amazon
There is also an Extra Fine version

Norton Norax belts
pricey but good
Have to search to find but Texas Knifemaker's Supply regularly carries https://www.texasknife.com
Come in up to at least 3000 grit, about $12 per belt.

600 grit

1200 grit

Good for putting edge on a knife

I have belts up to 2000 grit. After that, for polishing steel (or aluminum), I use 3M Trizact disks in 35, 10, and 5 micron grits in a random orbital sander and final polish with 3M Fine Machine Polishing Compound on a buffing wheel. Gives a mirror finish. (But, as I've been told many times, avoid a 'mirror' finish - it shows every flaw. (but done right it's exquisite))