Depends what you want.
Carrying laptop to work and home?
Look at Aer bags.
Want budget options?
Look at TomToc bags.
Want cute?
Look at Doughnut bags.
I love, but don't own Troubadour Apex
Want bomb proof? Hurl it down a mountain and it'll survive? GoRuck bags.
Or want simple, a decent bag for the cost that looks fine for daily but also nice on a country walk or visit to the peak district?
Google: Osprey Daylite Plus or Patagonia Atom.
Couple of my favourites, some i own, some I dpont:
(Just copy and paste into Google)
Chrome Industries Ruckas 14L
Decathlon NH500 Escape Roll Top 23l
Osprey Daylite Plus
5.11 Rush 12
Troubadour Apex
Able Carry Daily
Doughnut Macaroon
PacSafe Go
Honourable mention of a bag that I think is beautiful:
Peak Design Everyday Totepack in Bone
........
That should get you started. 😁