Check Ebay for "Spur" metal shelving brackets & double-hole strips.

They go in & out of fashion so can be very cheap, are well made,
adjustable. You can get things like "book-ends" which are
"functionally attractive", typically red, white, cream, perhaps brown.
The cream is ok with "barley white", the white a little cold looking.
The adjustability is very welcome vs fixed brackets. Ideally, if you
can fix into a wall stud if plasterboard as with any brackets.