Synonyms for Unremarkable:

adj.

habitual (adjective)
routine.
ordinary (adjective)
run-of-the-mill, indifferent, everyday, undistinguished, commonplace, standard, formulaic, quotidian, mediocre, cut-and-dried, usual, garden-variety, routine, average, stock, garden, unexceptional, plain, common.
unexceptional (adjective)
unexceptional.

n.

run-of-the-mill, standard, good, garden-variety, stock, usual, indifferent, mediocre, cut-and-dried, unexceptional, plain, common, commonplace, undistinguished, formulaic, garden, nondescript, average. unremarkable (noun)
mundane, workaday, routine, everyday, ordinary, quotidian.

Other synonyms:

unexceptional, garden-variety, nondescript, formulaic, cut-and-dried. mediocre, run-of-the-mill, garden. commonplace. average. indifferent. plain. commonplace
common.
ordinary
undistinguished, ordinary.
Other relevant words:
run-of-the-mill, standard, good, garden-variety, stock, usual, indifferent, mediocre, cut-and-dried, unexceptional, plain, common, commonplace, undistinguished, formulaic, garden, nondescript, average.