Synonyms for Knickknack:

n.

schlock, steal, bargain, knockoff, fixer-upper, cheapie, tat. thing, gimcrack, Bibelot, toy, trifle. curiosity (noun)
conversation piece.
knickknack (noun)
nicknack, Bric-a brac, whatnot, knickknackery.
ornament (noun)
gingerbread.
trifle (noun)
whatnot.
trinket (noun)
Bibelot.
trinket; decorative piece (noun)
embellishment, curiosity, toy, frill, furbelow, whimsy, whatnot, trapping, curio, trifle, device, conversation piece, gadget, showpiece, Bibelot, plaything.

v.

ornament (verb)
furbelow, gadget, frill, gingerbread, embellishment, curiosity, collectible, toy, kickshaw, conversation piece, trifle, device, showpiece, whimsy, thing, decoration, plaything, gimcrack, tchotchke, Bibelot, eye-catcher, curio, trapping.

Other synonyms:

schlock, fixer-upper, cheapie, tat, Bibelot. toy, gimcrack, decoration. bargain. steal. trifle. bric-a-brac
Bric-a brac.
Other relevant words:
gimcrack, trifle, steal, tchotchke, kickshaw, showpiece, knockoff, schlock, tat, bargain, decoration, conversation piece, collectible, plaything, thing, whimsy, trapping, cheapie, gingerbread, furbelow, device, curiosity, Bibelot, toy, gadget, embellishment, curio, frill.