You can get a box of about 170 Erbaur bits, up to and including 6mm for about £30 from Screwfix, I've not broken one yet.
I suspect that the Dormer HSS ones from the likes of Cromwell tools would cover your needs for larger sizes at sensible money
Dewalt extreme for me as well. Very good set with plenty of in between sizes not usually provided.Dewalt extreme are my go too ones the pilot bit on the tip of each bit is a god send https://www.screwfix.com/p/dewalt-extreme-2-hss-drill-bit-set-29pc/20064
Although if you use the same sizes all the time then just buy them individually